Optical Tweezers Poster
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P6  Clamping DNA Strands Together: Nano-Mechanics of Homologous
Recombination
Marcel Ander, Erik Schäffer
Biotec TU Dresden
Tatzberg 47-51
01307 Dresden, Germany
Homologous recombination is the key biological process for exchanging DNA segments
between two DNA molecules. It serves to repair DNA double strand breaks, re-launch stalled
replication forks, and maintains genetic diversity by mediating horizontal gene transfer
mechanisms such as conjugation and meiotic recombination. In all of these processes, a
segment of DNA is stably integrated into the recipient DNA.
Utilizing optical tweezers we analyzed the DNA single-strand annealing mechanism of
homologous recombination studying the phage lambda protein Redbeta. Redbeta is the main
actor in a technique termed recombineering ensuring efficiency of the recombination process.
Notably, Redbeta does not need nucleoside triphosphates as an energy source, such as RecA
or Rad51 do.
We discovered that Redbeta can actually block annealing of complementary DNA strands, and
will be active towards the 3' end of a complementary single-stranded DNA. Further, if
sufficient complementarity is given, Redbeta clamps complementary DNA strands together
and holds them. This sheds light onto the mechanism of DNA single-strand annealing.
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Scanning Probe Microscopy & Optical Tweezers in Life Sciences  6/7 October 2010 in Berlin
www.nanobioviews.net
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Optical Tweezers Poster
.
.
Scanning Probe Microscopy & Optical Tweezers in Life Sciences  6/7 October 2010 in Berlin
www.nanobioviews.net
2/2