Antipairing and strand transferase activities of E. coli helicase II (UvrD).
The product of the uvrD gene of Escherichia coli, UvrD (helicase II), is known to be involved in methyl-directed mismatch repair, transposon excision and uvrABC excision repair. In conjugational crosses, various uvrD mutants have been reported to result in higher, lower or unaffected recombination frequencies. In an attempt to clarify the role of UvrD in recombination, we have studied in vitro its effects on two key reactions driven by RecA, homologous pairing and strand exchange. We show here that UvrD efficiently prevents or reverses RecA-mediated homologous pairing. Unexpectedly, we also found that it can stimulate RecA-driven branch migration and even catalyze strand exchange in the absence of RecA. A possible in vivo role for these antagonistic activities is discussed.
Morel
P
P
Laboratoire de Génétique Microbienne, Institut National de la Recherche Agronomique, Jouy en Josas, France.
Hejna
J A
JA
Ehrlich
S D
SD
Cassuto
E
E
D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000378:metabolism; D001482:Base Composition; D004265:DNA Helicases; D004260:DNA Repair; D004279:DNA, Viral / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins; D011938:Rec A Recombinases / Q000378:metabolism; D011995:Recombination, Genetic
D004279:DNA, Viral; D029968:Escherichia coli Proteins; D011938:Rec A Recombinases; D000251:Adenosine Triphosphatases; C506746:UvrD protein, E coli; D004265:DNA Helicases