Biological significance of facilitated diffusion in protein-DNA interactions. Applications to T4 endonuclease V-initiated DNA repair.

摘要: Facilitated diffusion along nontarget DNA is employed by numerous DNA-interactive proteins to locate specific targets. Until now, the biological significance of scanning has remained elusive. T4 endonuclease V a repair enzyme which scans and processively incises at site pyrimidine dimers are produced exposure ultraviolet (UV) light. In this study we tested hypothesis that there exists direct correlation between degree processivity wild type mutant molecules enhanced UV resistance conferred repair-deficient Eshcerichia coli. This was accomplished first creating series mutants whose in vitro catalytic activities were shown be very similar enzyme. However, when mechanisms these enzymes search for its substrate analyzed vivo, displayed varying degrees ranging from being nearly as processive randomly incising within population. The ability altered enhance survival E. coli then assessed. directly correlated with level facilitated diffusion. conclusive evidence relating reduction vivo change an observed phenotype. These results support assertion employ locating their target sites significance.