Institut Curie / Inserm U 1006
Atomic Force Microscopy of
membrane proteins
Unit director: Simon Scheuring, PhD
We perform high-resolution and high-speed atomic
force microscopy (AFM) imaging and force
spectroscopy of membrane proteins. We are
interested in the structure, assembly and dynamics
of membrane proteins in native membranes, crucial
for a complete understanding of a membrane
protein. AFM experiments are performed in
physiological buffer at room temperature and under
normal pressure. High-resolution AFM features an
outstanding
signal-to-noise
ratio
allowing
membrane proteins to be directly visualized at
submolecular resolution. While high-speed AFM
can reveal membrane protein dynamics, AFMbased force spectroscopy measurements unravel
the interaction forces and energies between the
molecules. We aim at comparing the native
structures and assemblies with pathological cases
in order to pinpoint the basis of pathologies at the
single-molecule level.
Simon Scheuring, PhD
Membrane structure, Membrane protein, Atomic force
microscopy
Institut Curie / Inserm U 1006
11, rue Pierre et Marie Curie
75248 Paris Cedex 05
Tel : +33 1 56 24 67 81
Fax : +33 1 40 51 06 36
Email : [email protected]
KEYWORDS :
Membrane structure, Membrane protein, Atomic force microscopy, Force spectroscopy,
Electron microscopy, Membrane channel, Ion channel, Water channel, Receptor, Single
molecule biophysics, Single molecule imaging, Nano-biology, Nano-medicine, Nanotechnology
We perform high-resolution atomic force microscopy (AFM) level. HS-AFM movies of the membrane diffusion dynamics and
imaging and force spectroscopy of membrane proteins. We dimerization interaction of individual transmembrane proteins
are interested in "the structure and assembly of membrane can now be observed (Figure 2)
proteins in native membranes studied by atomic force
microscopy".
Figure
1:
Junctional
microdomains in healthy and
cataract lens membranes. A)
Deflection image of a native
membrane patch isolated
from the lens core. Junctional
microdomains
appear
as
corrugated
patches
distributed in the membrane.
B) and C) Topographs of
aquaporin 0 (AQP0) arrays
surrounded and separated by
densely packed or single rows
(arrowheads
in
B)
of
connexons. D) In the cataract
membrane connexons are
absent and malformed AQP0
micro-domains result. Cells in
the cataract lens starve due to
the absence of connexon
metabolite channels.
Figure 2: A high-speed atomic
force microscope (HS-AFM)
prototype
featuring
small
(8µm) cantilevers with high
resonance frequency (top)
allowed
the
direct
visualization of unlabelled
membrane protein dynamics
in membranes.
Here, the
assembly dynamics of ATPsynthase c-rings. HS-AFM
allows imaging about 1000 x
faster than conventional AFM.
Recent/Key Publications
Casuso I et al. (2010) Experimental evidence for membranemediated protein-protein interaction. Biophys J, 2010, in press
Buzhynskyy N et al. (2007) Human cataract lens membrane
at subnanometer resolution. J. Mol. Biol., 374 (1): 162-169
Buzhynskyy N et al. (2007) The supramolecular architecture
of junctional microdomains in native lens membranes. EMBO
R., 8 (1): 51-55
Gonçalves RP et al. (2006) 2-Chamber-AFM: Probing
Membrane Proteins Separating Two Aqueous Compartments.
Nature Methods, 3 (12): 1007-1012
Scheuring S and Sturgis J (2005) Chromatic adaptation of
photosynthetic membranes. Science, 309 (5733): 484-487
Information
concerning
structure,
function
related
conformational changes, and supramolecular assemblies, Patent available for licensing : 1
crucial for a complete understanding of a membrane protein,
can be contributed by AFM. AFM experiments are performed
in physiological buffer at room temperature and under normal
pressure. The AFM features an outstanding signal-to-noise
ratio allowing membrane proteins to be directly visualized in
their native environment, the native membrane. Only in the
native membrane can the native supramolecular assemblies,
i.e. nanometric machines constituted of several membrane
proteins
working
together,
be
observed.
These
supramolecular assemblies function in signal and energy
transduction with impressive efficiency. We reported highresolution images of aquaporins and connexons in junctional
microdomains in healthy and pathological eye lens
membranes (Figure 1).
Most recently, we set up a high-speed atomic force
microscopy (HS-AFM) prototype. HS-AFM allows the study of
dynamic biological processes. The spatial and time
resolutions of HS-AFM are of the order of nanometers and
milliseconds, respectively, and allow structural and functional
characterization of biological processes at the single-molecule