The DinI and RecX proteins are competing modulators of RecA function.
The DinI and RecX proteins of Escherichia coli both modulate the function of RecA protein, but have very different effects. DinI protein stabilizes RecA filaments, preventing disassembly but permitting assembly. RecX protein blocks RecA filament extension, which can lead to net filament disassembly. We demonstrate that both proteins can interact with the RecA filament, and propose that each can replace the other. The DinI/RecX displacement reactions are slow, requiring multiple minutes even when a large excess of the challenging protein is present. The effects of RecX protein on RecA filaments are manifest at lower modulator concentrations than the effects of DinI protein. Together, the DinI and RecX proteins constitute a new regulatory network. The two proteins compete directly as mainly positive (DinI) and negative (RecX) modulators of RecA function.
Department of Biochemistry, University of Wisconsin-Madison, 433 Babcock Drive, Madison, WI 53706-1544, USA.
Shelley L
SL
Lusetti
Julia C
JC
Drees
Elizabeth A
EA
Stohl
H Steven
HS
Seifert
Michael M
MM
Cox
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000502:physiology*; D000255:Adenosine Triphosphate / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry / Q000502:physiology*; D003001:Cloning, Molecular; D004247:DNA / Q000737:chemistry; D004265:DNA Helicases / Q000737:chemistry / Q000502:physiology*; D004307:Dose-Response Relationship, Radiation; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000502:physiology*; D006868:Hydrolysis; D008954:Models, Biological; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011938:Rec A Recombinases / Q000737:chemistry; D013997:Time Factors; D014466:Ultraviolet Rays
D001426:Bacterial Proteins; C422844:DinI protein, E coli; D029968:Escherichia coli Proteins; C430523:RecX protein, Xanthomonas campestris; D000255:Adenosine Triphosphate; D004247:DNA; D011938:Rec A Recombinases; D000251:Adenosine Triphosphatases; D004265:DNA Helicases