Print Email Facebook Twitter Human Rad51 filaments on double- and single-stranded DNA: Correlating regular and irregular forms with recombination function Title Human Rad51 filaments on double- and single-stranded DNA: Correlating regular and irregular forms with recombination function Author Ristic, D. Modesti, M. Van der Heijden, T. Van Noort, J. Dekker, C. Kanaar, R. Wyman, C. Faculty Applied Sciences Department Kavli Institute of Nanoscience Delft Abstract Recombinase proteins assembled into helical filaments on DNA are believed to be the catalytic core of homologous recombination. The assembly, disassembly and dynamic rearrangements of this structure must drive the DNA strand exchange reactions of homologous recombination. The sensitivity of eukaryotic recombinase activity to reaction conditions in vitro suggests that the status of bound nucleotide cofactors is important for function and possibly for filament structure. We analyzed nucleoprotein filaments formed by the human recombinase Rad51 in a variety of conditions on double-stranded and singlestrandedDNAby scanningforce microscopy. Regular filaments with extended double-stranded DNA correlated with active in vitro recombination, possibly due to stabilizing the DNA products of these assays. Though filaments formed readily on single-stranded DNA, they were very rarely regular structures. The irregular structure of filaments on single-stranded DNA suggests that Rad51 monomers are dynamic in filaments and that regular filaments are transient. Indeed, single molecule force spectroscopy of Rad51 filament assembly and disassembly in magnetic tweezers revealed protein association and disassociation from many points along the DNA, with kinetics different from those of RecA. The dynamic rearrangements of proteins and DNA within Rad51 nucleoprotein filaments could be key events driving strand exchange in homologous recombination. To reference this document use: http://resolver.tudelft.nl/uuid:b79fe7b6-2481-4444-9295-251a16eefba4 Publisher Oxford University Press Embargo date 2005-06-08 ISSN 0305-1048 Source Nucleic Acids Research, 33 (10), 2005 Part of collection Institutional Repository Document type journal article Rights (c) 2005 The Author(s) Files PDF vanderHeijden_2005.pdf 5.52 MB Close viewer /islandora/object/uuid:b79fe7b6-2481-4444-9295-251a16eefba4/datastream/OBJ/view