Bacillus subtilis RecU Holliday-junction resolvase modulates RecA activities.
The Bacillus subtilis RecU protein is able to catalyze in vitro DNA strand annealing and Holliday-junction resolution. The interaction between the RecA and RecU proteins, in the presence or absence of a single-stranded binding (SSB) protein, was studied. Substoichiometric amounts of RecU enhanced RecA loading onto single-stranded DNA (ssDNA) and stimulated RecA-catalyzed D-loop formation. However, RecU inhibited the RecA-mediated three-strand exchange reaction and ssDNA-dependent dATP or rATP hydrolysis. The addition of an SSB protein did not reverse the negative effect exerted by RecU on RecA function. Annealing of circular ssDNA and homologous linear 3'-tailed double-stranded DNA by RecU was not affected by the addition of RecA both in the presence and in the absence of SSB. We propose that RecU modulates RecA activities by promoting RecA-catalyzed strand invasion and inhibiting RecA-mediated branch migration, by preventing RecA filament disassembly, and suggest a potential mechanism for the control of resolvasome assembly.
Carrasco
Begoña
B
Departmento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC C/Darwin 3, Campus Universidad Autónoma de Madrid, 28049 Madrid, Spain.
Ayora
Silvia
S
Lurz
Rudi
R
Alonso
Juan C
JC
D000255:Adenosine Triphosphate / Q000378:metabolism; D001412:Bacillus subtilis / Q000201:enzymology*; D001426:Bacterial Proteins / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D003838:Deoxyadenine Nucleotides / Q000378:metabolism; D045565:Holliday Junction Resolvases / Q000378:metabolism*; D011938:Rec A Recombinases / Q000378:metabolism*
D001426:Bacterial Proteins; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D003838:Deoxyadenine Nucleotides; D000255:Adenosine Triphosphate; D011938:Rec A Recombinases; D045565:Holliday Junction Resolvases; C026600:2'-deoxyadenosine triphosphate