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RuvAB‐directed branch migration of individual Holliday junctions is impeded by sequence heterology
Author(s) -
Dennis Cynthia,
Fedorov Andrei,
Käs Emmanuel,
Salomé Laurence,
Grigoriev Mikhail
Publication year - 2004
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600249
Subject(s) - biology , holliday junction , sequence (biology) , branch migration , evolutionary biology , base sequence , genetics , computational biology , gene , recombination
The Holliday junction, the key intermediate of recombination, is generated by strand exchange resulting in a covalent connection between two recombining DNA molecules. Translocation of a Holliday junction along DNA, or branch migration, progressively exchanges one DNA strand for another and determines the amount of information that is transferred between two recombining partners. In Escherichia coli , the RuvAB protein complex promotes rapid and unidirectional branch migration of Holliday junctions. We have studied translocation of Holliday junctions using a quantitative biochemical system together with a ‘single‐molecule’ branch migration assay. We demonstrate that RuvAB translocates the junctions through identical DNA sequences in a processive manner with a broad distribution of individual branch migration rates. However, when the complex encounters short heterologous sequences, translocation of the Holliday junctions is impeded. We conclude that translocation of the junctions through a sequence heterology occurs with a probability of bypass being determined both by the length of the heterologous region and the lifetime of the stalled RuvAB complex.