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Struther Arnott. 25 September 1934 −− 20 April
2013
Sir Dai Rees
Biogr. Mems Fell. R. Soc. 2015 61, 5-22, published 26 August 2015 originally
published online August 26, 2015
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STRUTHER ARNOTT
25 September 1934 — 20 April 2013
Biogr. Mems Fell. R. Soc. 61, 5–22
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STRUTHER ARNOTT
25 September 1934 — 20 April 2013
Elected FRS 1985
By Sir Dai Rees* FRS
Formerly of the Medical Research Council, 1 Kemble Street,
London WC2B 4AN, UK
Struther Arnott worked tirelessly as a researcher, teacher, leader and maker and implementer of
policy in universities in Britain and the USA, always carrying his colleagues along with him
through his infectious energy and breadth of academic enthusiasms and values. His outlook was
shaped by the stimulus of a broad Scottish education that launched wide interests inside and
outside science, including the history and literature of classical civilizations. His early research,
with John Monteath Robertson FRS, was into structure determination by X-ray diffraction
methods for single crystals, at a time when the full power of computers was just becoming
realized for solution of the phase problem. With tenacity and originality, he then extended
these approaches to materials that were to a greater or lesser extent disordered and even more
difficult to solve because their diffraction patterns were poorer in information content. He
brought many problems to definitive and detailed conclusion in a field that had been notable for
solutions that were partial or vague, especially with oriented fibres of DNA and RNA but also
various polysaccharides and synthetic polymers. His first approach was to use molecular model
building in combination with difference Fourier analysis. This was followed later, and to even
greater effect, by a computer refinement method that he developed himself and called linkedatom least-squares refinement. This has now been adopted as the standard approach by most
serious centres of fibre diffraction analysis throughout the world. After the 10 years in which he
consolidated his initial reputation at the Medical Research Council Biophysics Unit at King’s
College, London, in association with Maurice Wilkins FRS, he moved to Purdue University in
the USA, first as Professor of Biology then becoming successively Head of the Department of
Biological Sciences and Vice-President for Research and Dean of the Graduate School. As well
as continuing his research, he contributed to the transformation of biological sciences at that
university and to the development of the university’s general management. He finally returned to
his roots in Scotland as Principal and Vice-Chancellor of the University of St Andrews, to draw
* [email protected]
http://dx.doi.org/10.1098/rsbm.2015.0011
7
© 2015 The Author(s)
Published by the Royal Society
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Biographical Memoirs
on his now formidable experience of international scholarship and institutional management, to
reshape the patterns of academic life and mission to sit more happily and successfully within
an environment that had become beset with conflict and change. He achieved this without
disturbance to the harmony and wisdom embodied in the venerable traditions of that ancient
Scottish yet cosmopolitan university.
Early life
Struther was born in Larkhall, a small town on the edge of the Clyde Valley close to Glasgow.
A pen portrait in a respected Scottish broadsheet newspaper, The Scotsman (Anon. 2007),
described Larkhall as having a reputation as ‘Scotland’s most sectarian community’. A culture
of conflict had arisen there 150 years ago in bitter industrial disputes in local coal mines. Mine
owners seeking to hold down wages and avoid the expense of safety improvement recruited
Irish immigrants as strikebreakers. These unfortunate refugees from famine were Catholics
conscripted into the position of threatening to take the jobs of indigenous Protestants. This
generated hostility towards them that has continued down the years and is still routinely
displayed in the flaunting of cultural symbols of Scottish Protestantism—tattoos, marching
bands, and football shirts in the colours of Rangers (the Protestant team in Glasgow). Although
the colour green is generally associated with pastoral tranquillity in other places, in the west
of Scotland it is a totem of Celtic Football Club, hence of the Catholic Church and so a
provocation to vandalism. Even the existence of green traffic lights was scapegoated, and
more than 200 of them were destroyed in the three years before this newspaper account.
Struther always spoke of his home town with a bemused, somewhat weary, affection
that seemed to me to hint at the irony that his own sanguine perspectives on life and human
nature had developed in such a place and where he had had to battle to hold to them. He had
a strong aversion to the vacuity that can stem from visceral prejudice of any kind, whether in
the conflicted environment of Larkhall or elsewhere. He found their equivalents in later life,
even among persons of learning and academic distinction, and always frowned and winced
at examples such as sentimentality posing as noble motive, favouritism trumping merit, and
wishful thinking clouding the interpretation of evidence. Ever courteous and well-mannered
in public, Struther was wont to brood over such follies in private, to polish elegant and
devastating arguments to challenge them when the time was right. This was typical of his habit
of careful deliberation over strategies to adopt in conflict situations, and it was one secret of
his effectiveness in the management of academic institutions. He was a moral person who
invented a personalized version of secular Scottish Calvinism for himself. He took great pride
in this tradition. His moral intensity could sometimes make him seem a little old-fashioned,
an impression that he rather liked to cultivate through minor eccentricities such as a pocket
watch and chain draped across a waistcoat, and a tendency towards quaint, slightly pompous,
but always precise and frequently amusing, punch lines to bring arguments to the crunch.
The Scotsman’s caricature of Larkhall might be a little overdrawn, written as it is in the
manner of rugged challenge, which is habitual to jousting Scottish masculinity, but Larkhall
was evidently something of a roughhouse and young Struther had to make his way in it.
There does seem to have been enough variety in social mix for him to find like-minded
contemporaries with whom to share the interests of his enquiring mind and draw him into the
society of his peers. This was important for a rather solemn and bookish boy with a mature
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S truther Arnott9
head on his young shoulders, an only child of parents who went their separate ways soon
after his birth. He developed an early fascination for birds and other wildlife and became very
knowledgeable about flora, fauna and country lore. He had a strong character and an amiable
disposition that could hold their own in the hurly-burly into which he was thrust. Beneath
the polished exterior that Struther presented to the world in later years, Larkhall did leave its
mark. I often reflected ‘you could take the boy out of Larkhall but you couldn’t take Larkhall
out of the boy.’ I think the influence served him well.
Little is known of Struther’s father, but his mother, Christina Struthers Arnott, was an
academic high-flyer who had been a brilliant student at Larkhall Academy, the first in the
family to receive university education. She graduated with the highest honours in chemistry
and mathematics at the University of Glasgow, the same degree in which Struther graduated
many years later. Opportunities to find a career through which to express a talent for scientific
creativity must have been very restricted for a girl at that time and place. She was obliged
to become a schoolteacher in the south of England, leaving Struther to be brought up by
her mother, Struther’s grandmother, returning when she could, for example in long school
holidays, to encourage the boy’s development and education. It was through her efforts
and insistence that Struther entered Hamilton Academy, a school famous nationally and
internationally for educational excellence. He flourished academically there and left with top
prizes for school achievement, having won first science place in the University of Glasgow
Open Bursary Competition. He was now poised to launch into a career that would live out the
unfulfilled ambitions of his gifted parent.
Struther’s grandmother, Elizabeth Meiklem Arnott, to whom fell the day-to-day responsibility
for bringing up Struther, was also a determined and capable woman. She married late from
and into a farming community. Her favourite son, Struther’s uncle, enlisted secretly and under
age for World War I and was killed. Struther seems to have become a surrogate for this loss.
She, too, must have been ambitious for Struther, but the boy seems to have been strong and
able enough to carry a double burden of family expectations. She schooled him in the common
sense and responsible citizenship that he displayed throughout his life. Evidently she had
management acumen and enterprise at a high level, as well as shrewd insight into people. With
her family background in successful farming, she established herself as a specialist in turning
around failing farms. She would present an analysis of the problems as she saw them with
animals, husbandry and finances, and stay until all were corrected. Struther’s approach to the
institutional reforms on which he was to embark in later life may well have been sustained by
her model. As the Americans would say, she had a ‘can do’ spirit, which passed on to him. He
often recalled her aphorisms and dictums.
University of Glasgow
By the time that Struther arrived in Glasgow University in 1952 his academic interests were
centred on physical sciences and mathematics but he also threw himself into extracurricular
activities. His social circle was formed at first around classmates in the so-called Alchemists’
Club, which was one of the oldest and best-established student organizations on campus. It
ran a broad programme of social events and lectures by distinguished speakers from outside
the university. He played a leading part in organizing the proceedings, planning programmes,
selecting distinguished guests and entertaining them during their visits. He expanded his
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Biographical Memoirs
horizons and sharpened his intellectual and disciplinary standards in conversations with them
and with anyone else he could entice into discussions and disputations. In this intense social
life, always a good host, he developed a knowledge and discrimination of good food and fine
wines to become something of an expert. I am told that he was a lean young man in those days,
before a taste for good living helped morph him into the more generous profile of later years.
His interests extended into even wider affairs when he ran successfully for election to the
Governing Board of Glasgow University Union. He became interested in politics and enjoyed
taking part in university debates. He made new friends, which included some who would
become prominent national politicians—John Smith (future Leader of the Labour Party),
Donald Dewar (Secretary of State for Scotland, subsequently First Minister for Scotland) and
John MacKay (later Lord Mackay of Ardbrecknish and Deputy Leader of the Conservatives in
the Lords). He became interested in politics and read voraciously and widely about the history
and styles of political leadership and governance: how reformers actually achieved change:
how to choose when to dictate and when to persuade, and when to set aside squeamishness
in the use of force. He was especially interested in leaders who might be called the hard men
of history: generals and statesmen of the ancient world; for example the father of Alexander
the Great, Philip of Macedon, to whom the phrase ‘divide and rule’ has been attributed; Sulla
and Marius from ancient Rome. He saw Julius Caesar as a model of benevolent dictatorship.
He also pondered the views of the ancients on personal relationships, for example in the
poetry of Catullus. From later history, he was fascinated by the ideas of Machiavelli, the
early American Presidents, and General George S. Patton. I remember an occasion when he
and I had one of our regular meetings in the 1970s (I was based in Edinburgh then, and he
in London), ostensibly to discuss research into polysaccharide structures, to find that each
of us had independently become immersed and inspired by Antonia Fraser’s just-published
life of Oliver Cromwell (Fraser 1973). This challenged the erstwhile view of Cromwell as a
destructive and ruthless tyrant, and argued instead that he was a man who, although certainly
uncompromising, changed the course of history through positive vision and belief. There
seemed to be a degree of self-identification here. He probably also saw some of these heroic
depictions as resonating with the history behind the local struggles and hostilities in the
community of Larkhall. Struther was a down-to-earth man of firm principles about practical
situations rather than a philosopher of elaborated ideologies or theories of history and destiny.
I never detected any flicker of concern over matters of party politics, institutionalized religion
or metaphysical mysteries.
These consuming extramural pursuits were not, however, allowed to occupy his entire life
in Glasgow. He was caught up and indeed fired up by events in Glasgow Chemistry Initiated in
1955 by the arrival of D. H. R. (later Sir Derek) Barton FRS as Regius Professor of Chemistry.
Here (1)* is how Struther observed them and described how he felt at the time (John Monteath
Robertson (JMR) was Gardiner Professor and Head of Department):
It would have been perfectly thinkable that JMR might have completed his career presiding over
a large, impressive, but not particularly distinguished, chemistry department; supervising at an
arms-length a research group from which well-trained X-ray diffractionists would go off to serve
other university chemistry departments or the chemical industry. But such a quiet life was not
in the stars and the Glasgow chemical firmament was illuminated by the Bartonian comet that
streaked across its sky in 1954–7. What is interesting and impressive in retrospect is the speed
*Numbers in this form refer to the bibliography at the end of the text.
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S truther Arnott11
with which JMR adapted his department in general and his research group in particular to harness
this energetic perturbation. Postdoctoral workers came from all over the world and in numbers
that almost swamped the indigenous postgraduates. The departmental store could no longer
close for lunch breaks. Researchers worked days, evenings, nights, weekends. Laboratories were
re-equipped. More exciting visitors came to speak. Undergraduates were challenged to new levels
of intellectual effort. It was all very exciting. JMR with his well-selected team was at the heart
of this excitement since his newly arrived DEUCE computer liberated him from the stultifying
computing constraints which for so long had restricted the size and complexity of the problems he
knew how to solve but could not afford to tackle. Many of the important natural products being
examined by Barton’s army were complex and terpenoid and had structures that could be solved
speedily, completely and convincingly only by X-ray diffraction analysis. Almost overnight,
JMR abandoned his previous targets of investigation and turned his group’s entire attention
to producing heavy atom derivatives of complex natural products which could then have their
unknown structures completely determined by methods which he had pioneered nearly 20 years
before. Thus JMR’s career had a final 12-year blaze and a satisfying completeness which is not
the good fortune of most scientists.
This experience of academic renewal clearly gave inspiration to the young Struther as he
embarked on his own journey in scientific leadership. He had an inside view of it as the first
research student of the Barton–Robertson partnership. His project was the structure of limonin,
a six-ring furanolactone (C26H30O8) that is the bitter principle of citrus fruits. This was an
ambitious undertaking at that time. Notwithstanding Struther’s own comments (above) about
improvements being made in computers and programs, these tools were still rudimentary and
the number of atoms in limonin was at the upper limit then considered tractable. By calculating
phases from the position of the iodine atom in an iodoacetate derivative, he worked his way
to eventual success and graduated PhD in 1960.
Medical Research Council Biophysics Unit, King’s College, London
Struther was now committed to research into the structures of biological molecules with the use
of X-ray diffraction. He moved to London in 1960 as scientist in the Medical Research Council
(MRC) Biophysics Unit at King’s College, to continue in this direction, with Maurice Wilkins,
who was a founder member of the Unit and its deputy director. Wilkins had been excited by
earlier work of Oswald Avery ForMemRS and his colleagues which had demonstrated that
DNA was the genetic material. This conclusion was largely ignored and indeed disbelieved by
many, but Wilkins resolved to study its structure. The subsequent story leading to the proposal
of the DNA double helix by Watson and Francis Crick (FRS 1959) is well known and has been
widely popularized. The 1962 Nobel Prize in Physiology or Medicine was awarded to Crick,
Watson and Wilkins ‘for their discoveries concerning the molecular structure of nucleic acids
and its significance for information transfer in living material’.
The research programme at King’s had originated in collaboration between several scientists
there. In early 1950 Maurice Wilkins had met with the Swiss biochemist Rudolph Signer,
who had been a student of Hermann Staudinger’s at a time when chemists still disagreed
about the structures of synthetic and natural polymers (now to include DNA)—whether they
were held in macromolecular form by defined covalent bonding or by fleeting (‘colloidal’)
secondary associations. This argument is now settled in favour of covalent bonding. Signer
realized that if DNA were such a polymer and was to be prepared from living organisms
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with its native form preserved, it would be necessary to find ways of protecting its delicate
molecular organization. It would, for example, be expected to be sensitive to shear. Signer’s
DNA was very different from materials made previously, and he was generous enough
to provide Maurice with a supply for investigation. Maurice was intrigued to find novel
optical, mechanical and hydration properties that must indicate some ordering in the way that
individual molecules were assembled. By patient investigation and manipulation he was able
to prepare and mount fibres for Raymond Gosling, the PhD student under his supervision, to
obtain X-ray diffraction photographs with many well-defined spots on a clear background.
This showed that DNA could be truly crystalline! Another colleague, Alex Stokes, deduced
that this pattern must arise from a structure in helical form with defined symmetry and packing
dimensions. John (later Sir John) Randall FRS, the Unit’s director, had facilitated the work at
the level of general planning and also in some aspects of experimental design, for example to
replace air in the camera with hydrogen to decrease the scattering that hitherto had obscured
diffraction features, particularly at low angles. The project was joined in the following year
(1952) by Rosalind Franklin, returning from abroad to strengthen the expertise available to
the group in X-ray diffraction analysis. The responsibility for mentoring Gosling’s PhD work
was passed from Wilkins to her. She undertook a systematic study of the relationships between
hydration of the fibres and their diffraction patterns, and eventually established the distinction
between the so-called A and B forms that will be discussed below. She also began to make
progress with rigorous methods of interpretation including use of the Patterson function, also
to be mentioned below. The hydration studies had now set up a situation in which Gosling
could record a second ground-breaking diffraction photograph. Controversially, and for better
or worse, this passed into the hands of the Cambridge group (Watson and Crick) to give them
the starting point for their historic dash for priority in building a plausible molecular model. In
the years that followed, many articles, books and media programmes have explored the rights
and wrongs of these developments and the personal conflicts associated with them. I will not
venture again into those arguments because they have already been so extensively debated.
Struther Arnott joined the group a few years later, by which time the dust had settled a little,
to the extent that it ever did. His arrival was too late for him to observe the early events at first
hand but he could not fail to hear all about them from those protagonists whom he came to
know personally (except Franklin, who died prematurely in 1958). His thoughtful and wellinformed assessment is included in his memoir of Maurice Wilkins (2).
As Watson (1968) tells his side of the story, as soon as he and Crick had built their threedimensional model it was immediately seen to provide a single picture into which many
independent and unrelated observations clicked like pieces in a jigsaw puzzle: the covalent
structure of the chain already established by A. R. (later Lord) Todd FRS (PRS 1975–80) and
his group in Cambridge; the symmetry and spacings of Gosling’s second remarkable X-ray
diffraction pattern that had become available to Watson and Crick; the rules derived by Erwin
Chargaff from his extensive analysis of the base composition of DNA samples from a variety
of sources, indicating some regularities in structure because the content of adenine always
matched that of thymine and likewise guanine with cytosine; the insistence of Jerry Donohue,
then a research visitor fortuitously sharing an office with Watson in Cambridge, that thymine
and guanine had to exist as keto tautomers rather than, as the text books then had it, as enols;
arguments advanced by Rosalind Franklin from the physical chemistry of hydration that the
phosphate groups had to be on the outside of any structure; the confirmation of this from her
calculation of Patterson functions to show the distances between atoms with greatest power to
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S truther Arnott13
scatter X-rays (namely phosphorus); the similarity of shape between the two sets of purine–
pyrimidine pairs, the hydrogen-bonding pattern within base pairs; the neat packing together
of all atoms in the structure without gaps or clashes; and above all the exciting recognition of
the complementarity of strands and what it could mean for genetic replication. This was one
of the great eureka experiences of all time which many people quickly bought into, an insight
that set the whole science of biology on a new course. But it would be wrong to say that the
structure was ‘proved’ and that the structure of genetic material was now established fact.
More questions remained.
Other models could be built that were just as attractive. Now returned to America, Jerry
Donohue pointed out (Donohue 1969) that Watson and Crick had chosen only one possible
arrangement for base pairing, and that a further 28 remained to be considered! Watson and
Crick had not shown whether their model was consistent with all the evidence from X-ray
diffraction, having used only the spacings between the spots and the symmetry in their
pattern, and it had yet to be shown whether the model really fitted the intensities of them.
The spacings gave information about geometrical properties such as the helical structure, like
a staircase with 10 steps (taken by Watson and Crick as being base pairs) per turn rising in
2.8 nm. The class of symmetry favoured a double (rather than, say, a triple) helix, with the
two chains pointing in opposite directions. Rosalind Franklin’s calculations showed some
encouraging consistency of intensities with the backbone arrangement proposed, but a detailed
comparison of them with predictions from the atomic positions in the model was beyond
the scope of techniques available at that time. Initial attempts by Watson and Crick had not
been encouraging, because they found that the standard index of comparison (the so-called
R-factor) between the measured and calculated intensities was very poor indeed—0.85, far
from the value of about 0.2 expected for a structure that was at least approximately correct,
and even worse than the value of 0.59 expected for a structure that was completely wrong.
As Struther commented later, ‘the details of that model were entirely unsupported by the
[intensities in the] diffraction data.’
The scientific world was divided between a larger camp of would-be believers in the
double helix structure, excited by new lines of thinking and experiment that this now opened
up, and a camp of sceptics that was smaller but included many experts, some of whom had
been competitors in the race for the structure and were still interested in the possibility of a
different solution. Crick, Watson and Wilkins did not allow any wishful thinking to tilt them
towards overstating any claims; they had put forward their best working hypothesis and would
await the verdict of further research. Crick and Watson were by now (separately) following
other interests, but Wilkins dedicated the efforts of his research group—now augmented by the
recruitment of Struther—to taking the investigation through to completion. Stakes were high
because everybody could now see how important this problem was, and personal scientific
reputations were on the line. There was always something of the poker player about Struther,
and I think he relished the role of the cool head among viscerally committed partisans (shades
of Larkhall and no doubt debates in the Glasgow Union too).
Wilkins, with other colleagues, improved the design of X-ray cameras and the techniques of
fibre diffraction and found ways of preparing purer and better samples of DNA and of aligning
the molecules to give better diffraction patterns; computers were exploited more as their power
increased. Struther’s role, for which his knowledge and aptitude in mathematics suited him
perfectly, was to determine whether the model could be refined into a satisfactory quantitative
match with the intensity measurements. Watson and Crick could only adjust wire frameworks
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Biographical Memoirs
that were much too crude for the purpose, but now computers were powerful enough for
Struther to develop new techniques for systematic and precise manipulation of models by
calculation rather than simply taking measurements with a ruler from physical models. He also
had to contend with the problem that the quality of the data that it was possible to obtain by
the method of X-ray diffraction analysis was not good enough for the precise localization of
atomic positions. This was because DNA does not form genuine crystals but merely fibres spun
or drawn so that the chain molecules are aligned lengthways but packed side-to-side in a more
or less jumbled fashion—sometimes with no regularity in packing side-to-side (as in the first
samples of the so-called B form of DNA) but sometimes with a degree of order (as in A-DNA).
When chains are not precisely located, they cannot, by definition, give photographs that define
exact positions, and the interpreter has to do the best he can in terms of average positions.
Struther approached this problem in two ways. The first was by showing that a method
for genuinely crystalline materials known as difference Fourier analysis pioneered by C. W.
Bunn (FRS 1967) (see below for other convergences of Struther’s interests with his) could
be adapted for DNA fibres. The phases of diffracted intensities would be calculated from a
provisional model (in this instance it would be the Watson–Crick structure) and combined
with the observed diffraction amplitudes—essentially the square roots of the measured
intensities—to produce the image of a new structure. This leads to a better model to provide
improved phases for another round of calculation, and so forth. As the quality of the intensity
data was steadily improved through the efforts of the experimentalists in Wilkins’s team, the
model steadily moved to better and better agreement. Struther’s second and more powerful
approach was to circumvent the inherent difficulties just mentioned in fibre as opposed to
crystal diffraction, by setting up the trial structure in the computer in such a way that it
offered far fewer structural variables for adjustment for a best match with intensities than in
conventional crystallographic refinement. Bond lengths, bond angles and minimum separation
distances between atoms to avoid steric clash could be confidently predicted from previous
work on simpler structures, so why throw these into the melting pot of refinement as though
they needed to be determined all over again? It would make better use of limited experimental
evidence to refine the fewer variables that remained when these were left out, mainly certain
dihedral angles; Struther did this with a mathematical tool new to X-ray analysis known as
Lagrange multipliers. His method of adopting a subset of values as givens was attacked by
some crystallographers as bad practice, even as a form of cheating, like solving a detective
mystery by taking a peek at the last page. It was fortunate that Struther enjoyed an argument
because he had plenty of these to contend with. His method has come to be known as LALS
(linked-atom least-squares refinement) and has been used successfully to investigate the
structures of a large number of more or less ordered polynucleotides, polysaccharides, proteins
and other fibrous materials, and is now widely adopted throughout the world.
At long last, good agreement was achieved for DNA, but it needed considerable changes
to the Watson–Crick model. It had to be recognized that, of the alternative pucker forms
possible for the rings of the sugar (deoxyribose) rings, Watson had chosen the wrong one for
the DNA structure for which he built the model (so-called B-DNA). This did not affect such
key features as the patterns of base pairing or hydrogen-bonding relevant to the function of
replication, which was of such interest to biologists. The wrong pucker for B-DNA turned out
to be the right one for the other DNA structure that they studied at the time (A-DNA), but this
required other adjustments such as tilting the base pairs and increasing the number of them in
each turn of helix from 10 to 11.
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S truther Arnott15
Controversy continued but gradually diminished, helped in 1973 when Alexander Rich
and his colleagues found that very short lengths of DNA could be induced to form crystals
for full X-ray analysis and the details were found to match the essential features of Watson
and Crick’s model. Even now, critics could and did complain that the crystal structure showed
only that DNA could adopt the Watson–Crick form and not necessarily that in living systems
it did. However, such voices were hardly taken seriously within the scientific community and
eventually fell silent.
An important phase of nucleic acid research had come to an end. The big questions now
were not so much about the details of DNA structure itself but rather of the relations between
structure and function. The major players moved on. Crick now worked with Sydney Brenner
FRS to make huge contributions to the understanding of how DNA worked in expressing the
genetic code; Watson moved to Harvard to develop molecular biology as a new discipline by
administration and by writing The molecular biology of the gene (Watson et al. 1987), and also
to research the role of RNA in the transfer of genetic information and instigate the discovery
of cancer genes; and Wilkins stayed at King’s College but shifted his research to the structure
of membranes, and increasingly concerned himself with questions of social responsibility in
science. It was time for Struther, too, to look for new challenges.
Purdue University
Struther accepted an invitation to become Professor of Biology at Purdue University in 1970.
He was now able to build a much larger research group, an opportunity that came at exactly
the right time because many fibre diffraction problems lay waiting for the ways forward that
had now been made possible by the concepts and methods he had developed for DNA. He
was now cast in a role rather like that he described for his mentor, John Monteath Robertson,
in Glasgow in the 1950s: organizing and directing a large team working on a range of related
problems. He remained very much the intellectual leader: it was his personal insights (which
were now ‘in his DNA’, as we might put it nowadays) that were key to progress. His influence
went beyond the domain of intellectual abstractions, however. His research team being largely,
if not entirely, made up of younger scientists still in training, he was always committed to
and enthusiastic about his responsibility as mentor to encourage both their personal and their
research development. He had a quality of human touch to inspire, challenge and encourage
independent creativity and scrupulousness in standards. For many his guidance and example
remained a lifelong influence.
By a systematic study of synthetic polynucleotides of defined sequence, Struther and his team
showed the influence of nucleotide sequence on the helical forms adopted by RNA and DNA.
It turned out that all the double-helical conformations available to RNA are very similar and
therefore that RNA helical structures are insensitive to composition and sequence. By contrast,
DNA has a great variety of polymorphic forms, the geometries of which can reflect sequence
peculiarities or respond to the local environment. This points to a variety of different possibilities
for the action of drugs and signalling molecules, which are still being explored by others.
Struther also broadened his interests to the extracellular polysaccharides of plants, animals
and bacteria, many of which are industrially useful or (for animal polysaccharides) relevant
in medical disorders, for example those of the connective tissues of skin, bones, joints and
eyes. Many new helical forms were discovered and characterized, some with a propensity for
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pairwise association, either coaxially or side by side. Collaborators such as my own group
showed that some of these could survive into hydrated environments to tie chains together for
structure-building properties.
The Department of Biological Sciences at Purdue was the creation of Henry Koffler,
who had been its head for more than 16 years. Within a single administrative structure, it
contained all the science disciplines traditionally represented by departments of biochemistry,
biophysics, botany, genetics, microbiology, physiology and zoology. All except three of the
54 faculty members had been appointed by Koffler. Struther came to like and respect him
very much. Although his professorial appointment had been made primarily for research, his
delight at the broad and refreshing sweep of topics and ideas in his new environment drew him
to go beyond the call of research duty to develop and contribute new courses to the teaching
programmes, and to take interest in general policy matters and discuss these with Koffler. He
was now in the mainstream of departmental life.
When Koffler decided that it was time for him to leave, Struther was the obvious heir
apparent. He was appointed Head of Biological Sciences in 1975. It was immediately clear that
his new job in those fast-moving times demanded that he keep the department abreast of, and
indeed get it ahead of, changing demands from the outside world. As was happening in society
generally, people (both students and staff) were calling for more transparency, democracy and
equality of opportunity in decisions, appointments, tenure, promotions and university response
to societal change. Teaching and research staff had to be continually refreshed by new blood
and fresh inspiration. Progress in science and the changing requirements of such customers
for university output as employers, government agencies and the public, required continuous
adaptation of teaching courses and research portfolios. Struther was helped at the outset by the
previous suspension of recruitment while Koffler was considering his new move. This gave
him the opportunity to make more than the usual number of new appointments. He seized this
to adjust the age profile of the department towards youth, increase the proportion of women,
strengthen the field of ecology within the department to reflect the increased priority of
issues of the natural environment, and similarly to enhance areas relevant to cancer research,
which had also become a greater local priority. In matters of teaching, foreshadowing similar
initiatives that he was to take later at St Andrews, he pressed for the university to become
greater than the sum of its parts by more cooperation between separate departments, including
his own. For example, he established the campus-wide Purdue University Biochemistry
Graduate Program, which became a model that was refined and adapted to other subject areas
elsewhere in the university.
Struther’s developing acumen and influence was recognized and given further scope by
his appointment to the position of Vice-President for Research and Dean of the Graduate
School in 1980. This was a school of some 6000 students, in a university having an annual
budget of more than half a billion dollars and a student population of 48 000. Struther joined
the Provost’s inner (five-member) ‘cabinet’. This included the Vice-Presidents for other areas
of university policy and met weekly to formulate all policies connected with the university’s
scholarship and teaching. Struther’s specific duties included deputizing for the Provost and
sharing with him the responsibility for quality control throughout the Purdue system such as
faculty promotions, regular reviews of academic departments by external experts, and internal
reviews of schools by the President. Struther himself oversaw the appointment of department
heads in Purdue’s nine schools and the distribution of about $2 million in faculty and graduate
student fellowships and grants.
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S truther Arnott17
Figure 1. Struther and Greta Arnott on a trip in the summer of 1985 to visit Paris
and the musée du Louvre. (Online version in colour.)
Struther was now a figure in international science. He travelled extensively to lecture,
collaborate and provide consultation on policy matters and had already taken one short spell
of sabbatical leave—at Jesus College, Oxford, sponsored by Sir David (later Lord) Phillips
FRS—from autumn 1979 to early 1980. He was overdue for a longer period of sabbatical
leave and took this as Nuffield Fellow at Green College, University of Oxford, for 1985–86.
This gave time and opportunities not only to refresh his scientific ideas but also with Greta, his
wife, to catch up with and enjoy again the cultural offerings now accessible in London, Oxford
and elsewhere (figure 1). These had been important to them in their years before moving—
theatres, films, galleries, restaurants, and meetings with kindred spirits across academic and
other interests.
Aaron, the Arnotts’ elder son, was firmly rooted with his own family and career in the
USA, but Euan, the younger, now in his early teens, came with them, and enjoyed a year of
British schooling and found that this suited him. The sabbatical experience was rejuvenating
and refreshed the appetite for things left behind when they had departed for the USA in 1970.
Despite the excitement and vitality of American life and Struther’s fascination with the New
World as a place where civilization was being remade on a different model (‘civilizations’
being one of Struther’s consuming extramural interests), a return to roots began to appeal. It
became apparent that the ancient University of St Andrews, founded in 1413, the third oldest
in the English-speaking world and—significantly for Struther—an important institution for
Scotland, was seeking a new Principal. The temptation of moving there simply had to be
investigated. In due course Struther was offered this appointment.
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University of St Andrews
British academia has traditionally differed from American in being averse to organization
and management. It has preferred to argue that free expression of the creative spirit is all that
is needed to justify the income to sustain university life in its intellectual vitality and such
tangible requirements as salaries, bricks and mortar, instruments, services, libraries, heating
and lighting. Times have changed, however, and any modern paymaster, whether the public
purse, an industrial sponsor or a philanthropic benefactor, needs to be assured that he is
funding the specific purposes he wishes to support. A modern university cannot present itself
as an unstructured association of undirected individuals but must be seen as a purposeful
organization with clarity of mission and visible plans of how this will be pursued. That
mission can by all means include the pursuit of dreams or blind exploration of the unknown
regardless of practical applications, but if so this must be explicit and up front. The challenges
facing Struther at St Andrews in 1986 had similarities to as well as differences from those at
Purdue. The smaller Scottish universities, of which St Andrews was one, had their own special
problems of being squeezed by financial pressures threatening their critical mass and viability
of infrastructure, and thus their very existence. (Edinburgh and Glasgow were perhaps more
comparable with Purdue.)
St Andrews was a small university of 3600 students, 3100 of whom were British and
250 were from the USA. Three local universities (Dundee, Stirling and Heriot-Watt) were
even smaller and were attempting to solve financial problems by slimming to focus mainly
on professional or vocational subjects, with Dundee and Stirling taking the drastic steps of
abandoning chemistry and physics. A little farther away, Aberdeen was moving to reduce or
relinquish classics, philosophy and histories. Like all others in UK, these universities needed
to show that they could attract worthy student applicants (in the jargon, the evidence of
demand for their products in the market). Struther decided that the movement of the other
institutions, which were his regional competitors in the direction of narrower focus, created
space for him to develop a different type of identity with a broad profile in the arts and basic
sciences, so that St Andrews could flourish more in the spirit of a true university. For example,
the retreat of the other institutions from departments of language, of philosophy and history of
science and of economic and social history left space for St Andrews to strengthen these areas.
Struther also recognized that efficiencies could be gained by expedients such as those he
had established at Purdue, for example in his campus-wide University Biochemistry Graduate
Program there. He argued successfully for the setting up of an ‘academic common market’
involving St Andrews, Dundee and Stirling in the sharing of academic services, exchange of
teaching and in the easy transference of students’ academic credit.
He reorganized the science departments at St Andrews into larger units (schools), which
could afford better technical infrastructure and carry more visible weight in the outside
world. Physics and Astronomy were consolidated into the centre of excellence of Physical
Sciences; the three departments of Pure and Applied Mathematics and Statistics into
Mathematical Sciences; Anatomy, Experimental Pathology, Physiology, Pharmacology, Plant
Biology and Ecology, and Zoology into Biological Sciences; and Geography and Geology
into Geosciences. This integration was implemented with internal remodelling to strengthen
particular disciplines that were likely to equip students better for wider and more attractive
employment possibilities, such as the chemistry of materials and the physics of lasers. He
established a Department of Management, invested in computer science and developed
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S truther Arnott19
external links through his academic common market with vocational courses in Dundee
and Stirling and with the Planning Unit of Shell International to bring its strategic planning
techniques into the university. The result was for St Andrews to continue to have the largest
honours school of mathematics in Scotland, and its Chemistry and Physics departments to be
the only ones in these disciplines north of the Forth to be officially assessed as in the top tier.
A similar programme of reform was conducted in the Arts and Humanities with, for example,
the formation of a School of History, a School of Modern Languages and a School of Classics.
Structural reform alone would not be sufficient to assure the future, however. The morale
and spirit of the institution also needed refreshment. Struther’s approach to this has been
eloquently sketched by Colin Vincent, once a fellow-student with Struther at Glasgow and
lately Head of Chemistry and Master of the United College at St Andrews, in a tribute
delivered at the Thanksgiving Service for Struther:
So Struther arrived at an institution which was neither a finishing school for Oxbridge rejects nor
a research desert—nor was it entirely true that the humanities curricula had remained virtually
untouched since 1413.
The University was, however, dispirited, inward-looking, Arts-biased and, frankly, had many
passengers on its staff. It was struggling with government-imposed cuts. The new Principal
came with a vision of what St. Andrews might become, and a drive to set it on its way. He saw
his appointment as sending a signal that St. Andrews was not willing to be a liberal arts college
and that while it must be primarily a Scottish institution, it should be a cosmopolitan one with
international ambitions. He often suggested that St. Andrews should seek comparison with ancient
Sparta—the ‘hard option place’, unlike the more effete Athens. In his early years here he instituted
root-and-branch changes to academic management, planning procedures, governance, finance and
fund-raising, and began the on-going investment in modern facilities. His critical contribution was
made, I believe, in the appointment of academic staff. He convened every appointment committee
and would regularly insist on no appointment if none of the candidates reached his exacting
standards. He travelled the globe to persuade those he thought world-class to leave their current
employment and come to St. Andrews.
Greta was a partner in Struther’s university life as well as in his family life. As a graduate in
English literature and language and with a wide interest in the arts, she found much to engage
her in the academic activities as well as in social and community affairs. Ever since his Glasgow
days, Struther had liked to shade the social and the intellectual sides of academic interchange
into each other, with his tradition of good dinners playing a prominent part. It was natural
for Greta to take initiatives when these had, for example, a literary flavour. With a constantly
changing population of staff, visitors, and postgraduate and undergraduate students she worked
hard to capitalize on the advantages of a small university by getting people to know and interact
with each other. The university recognized her diverse contributions with the honorary DLitt.
When the time came for retirement in 2000, Struther and Greta had very clear ideas for the
patterns their new lives were to take, and the new home they would need. They wanted style,
space and good rail access to London without the hassle of the UK road system. Ever since
youth, Struther’s imagination had been seized by a fascination with the variety of forms that
plant life could take, and this exercised his facility with systematically organized information
that befitted the budding crystallographer. This always spilled out as an eager and outgoing
enthusiasm and a compulsion to share the delights with others, which had won his following
of youthful disciples in Larkhall to help draw him into the crowd. With the extra freedom of
retirement, this continuing commitment could now be expressed in the creative cultivation
and enjoyment of plants. Struther and Greta found an elegant Georgian residence with mature
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Biographical Memoirs
Figure 2. Struther Arnott taking a break from his labours in his Yorkshire garden. (Online version in colour.)
landscaped gardens in South Yorkshire (figure 2), which was also sufficiently close to Euan
and his family. From here they could enjoy the theatre and the arts together, and Struther could
establish a new base for his science. They were eager to discover more of the classical world,
which was a great interest of them both. They took archaeological tours to Etruria to learn
more of the civilization that the Romans absorbed, and then to Sicily, Ravenna, Syria, Rome,
Lyon and Crete.
The family and research reasons for continued visits to the USA (Aaron now being settled
there and links with Purdue remaining very active) made opportunities for them to continue to
enjoy cultural activities there, especially in Washington and Los Angeles.
Struther took enormous pleasure in watching his grandchildren grow up. Since Euan’s
two were now nearby, he could read them stories, romp with them outdoors and take family
holidays together. He and Greta visited Aaron’s daughters, Ashley and Amber, annually
in California until long flights became problematic. He always had the gift of natural
communication with children. My own, now in their fifties, still remember vividly being
spellbound 45 years ago by his tales from the Lanarkshire countryside that he had heard
himself from his Granny Arnott.
Struther accepted a Visiting Professorship in John Squire’s department at Imperial College
in 2002, and a similar position in 2003 at the School of Pharmacy with Stephen Neidle. He
visited both regularly to keep abreast of current progress and to continue with several projects
of his own, mostly on structure determinations from previous years that he felt had still to
be brought to his high standards of completion. He also continued collaboration with former
colleagues at Purdue, especially Rengaswami Chandrasekaran, who had taken custody of
their joint programme into nucleic acid and polysaccharide structures when Struther left in
1986 (Chandrasekaran 2013). They had frequent telephone conversations, and occasional
visits while Struther was still able to take transatlantic flights, to mull over knotty problems
of interpretation of fibre diffraction that still niggled from years gone by, or that were current
in the Purdue laboratory.
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S truther Arnott21
Struther’s final research paper, a product of his energetic collaborations with various
groups at a distance in later years, was the derivation of a new and more soundly established
structure for crystalline natural rubber (3). This gave Struther particular satisfaction because
it built on the work of C. W. Bunn (1905–90), a pioneer of rigorous approaches to the
interpretation of fibre diffraction patterns from the 1930s onwards. Like Struther but with
the more limited means then feasible, he used model building to contend with the problem
of interpreting X-ray patterns in which the reflections were few in number and distorted in
quality. Bunn worked in industry on textile polymers, which were novel materials at the
time, including nylon and Terylene. Maurice Wilkins had consulted him as ‘the leading
figure in X-ray studies of fibres’ at the outset of his own DNA project, although this did not
lead to a working collaboration (Wilkins 2005). It was Bunn who conceived the design of
the wire framework models perfected later by John (later Sir John) Kendrew (FRS 1960) for
protein structures and then made famous by Watson and Crick in building the first model of
the DNA double helix with which they were photographed in a picture that was broadcast
across the world and published in almost every serious newspaper. This was the tradition
that Struther brought to fruition in the computer age in his LALS approach. Both Struther
and Bunn, although in different decades, had to prevail in arguments with those purists
who were reluctant to admit that the tangible representations of structural chemistry and
the mathematical abstractions of diffraction physics were necessary and complementary to
each other.
Struther fell ill in December 2012 and died four months later after hospital treatment for
hydrothorax and complications arising from infection. He is survived by Greta (née Edwards;
they married in 1970), Aaron and his daughters, Ashley and Amber, and Euan and his wife,
Frances, and their children, Kathryn and James.
Acknowledgements
I thank Greta Arnott for information about Struther’s family background and for many illuminating reminiscences
about his wider interests, values and pursuits. I am grateful to Colin Vincent for his insights and perspectives both
as a fellow-student with Struther at Glasgow and as his colleague through the reforms at St Andrews, and for
his permission to quote from his memorial address. I appreciate the generosity of Rengaswami Chandrasekaran,
Struther’s close research colleague at Purdue, in sharing at an early stage his own appreciation of Struther that was
subsequently published. Euan Arnott was a pillar of diligence and expertise in bibliographic work.
The frontispiece photograph was by Robin Gillanders and is reproduced with permission.
References to other authors
Anon. 2007 Nothing about Larkhall is black and white. The Scotsman (29 August). (See http://www.scotsman.com/
news/nothing-about-larkhall-is-black-and-white-1-916560.)
Chandrasekaran, R. 2013 Struther Arnott 1934–2013. Adv. Carbohydrate Chem. Biochem. 70, 2–12.
Donohue, J. 1969 Fourier analysis and the structure of DNA. Science 165, 1091–1096.
Fraser, A. 1973 Cromwell: our chief of men. London: Weidenfeld & Nicolson.
Watson, J. D. 1968 The double helix. London: Weidenfeld & Nicolson.
Watson, J. D., Hopkins, N. H. & Roberts, J. W. 1987 The molecular biology of the gene. San Francisco, CA:
Benjamin/Cummings.
Wilkins, M. H. F. 2005 The third man of the double helix: an autobiography. Oxford University Press.
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Bibliography
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2006 (With G. Rajkumar & J. M. Squire) A new structure for crystalline natural rubber. Macromolecules 39,
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