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Hallmarks of homology recognition by RecA‐like recombinases are exhibited by the unrelated Escherichia coli RecT protein
Author(s) -
Noirot Philippe,
Gupta Ravindra C.,
Radding Charles M.,
Kolodner Richard D.
Publication year - 2003
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 - 10.1093/emboj/cdg027
Subject(s) - haven , library science , art history , gerontology , art , medicine , computer science , mathematics , combinatorics
Homologous recombination is a fundamental process for genome maintenance and evolution. Various proteins capable of performing homology recognition and pairing of DNA strands have been isolated from many organisms. The RecA family of proteins exhibits a number of biochemical properties that are considered hallmarks of homology recognition. Here, we investigated whether the unrelated Escherichia coli RecT protein, which mediates homologous pairing and strand exchange, also exhibits such properties. We found that, like RecA and known RecA homologs: (i) RecT promotes the co‐aggregation of ssDNA with duplex DNA, which is known to facilitate homologous contacts; (ii) RecT binding to ssDNA mediates unstacking of the bases, a key step in homology recognition; (iii) RecT mediates the formation of a three‐strand synaptic intermediate where pairing is facilitated by local helix destabilization, and the preferential switching of A:T base pairs mediates recognition of homology; and (iv) RecT‐mediated pairing occurs from both 3′‐ and 5′‐single‐stranded ends. Taken together, our results show that RecT shares fundamental homology‐recognition properties with the RecA homologs, and provide new insights on an underlying universal mechanism of homologous recognition.