Mutants of phage bIL67 RuvC with enhanced Holliday junction binding selectivity and resolution symmetry.

ABSTRACT: Viral and bacterial Holliday junction resolvases differ in specificity with the former typically being more promiscuous, acting on a variety of branched DNA substrates, while the latter exclusively targets Holliday junctions. We have determined the crystal structure of a RuvC resolvase from bacteriophage bIL67 to help identify features responsible for DNA branch discrimination. Comparisons between phage and bacterial RuvC structures revealed significant differences in the number and position of positively-charged residues in the outer sides of the junction binding cleft. Substitutions were generated in phage RuvC residues implicated in branch recognition and six were found to confer defects in Holliday junction and replication fork cleavage in vivo. Two mutants, R121A and R124A that flank

SUBMITTER: Green V 

PROVIDER: S-EPMC3864405 | biostudies-literature | 2013 Sep

REPOSITORIES: biostudies-literature