Efficient coupling of ATP hydrolysis to translocation by RecQ helicase.

ABSTRACT: Helicases are ubiquitous enzymes that unwind double-stranded DNA (dsDNA) to reveal single-stranded DNA (ssDNA) during essential processes such as replication, transcription, or repair. The Escherichia coli RecQ protein is a 3' to 5' helicase, which functions in the processes of homologous recombination and replication fork restart. Here, we analyzed the relationship between ATP hydrolysis by RecQ and its translocation on ssDNA. We monitored a single round of RecQ translocation on ssDNA by measuring the rates of inorganic phosphate release during translocation, and the dissociation of RecQ from ssDNA. We find that RecQ translocates with a rate of 16( ± 4) nucleotides/s and moves on average only 36( ± 2) nucleotides before dissociating. Fitting to an n-step kinetic model suggests that the he

SUBMITTER: Rad B 

PROVIDER: S-EPMC3277138 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature