E. coli RecB Nuclease Domain Regulates RecBCD Helicase Activity but not Single Stranded DNA Translocase Activity.

ABSTRACT: Much is still unknown about the mechanisms by which helicases unwind duplex DNA. Whereas structure-based models describe DNA unwinding as occurring by the ATPase motors mechanically pulling the DNA duplex across a wedge domain in the helicase, biochemical data show that processive DNA unwinding by E. coli RecBCD helicase can occur in the absence of ssDNA translocation by the canonical RecB and RecD motors. Here we show that DNA unwinding is not a simple consequence of ssDNA translocation by the motors. Using stopped-flow fluorescence approaches, we show that a RecB nuclease domain deletion variant (RecB^ΔNucCD) unwinds dsDNA at significantly slower rates than RecBCD, while the ssDNA translocation rate is unaffected. This effect is primarily due to the absence of the nuclease doma

SUBMITTER: Fazio NT 

PROVIDER: S-EPMC11131135 | biostudies-literature | 2024 Jan

REPOSITORIES: biostudies-literature