Functional similarities between phage lambda Orf and Escherichia coli RecFOR in initiation of genetic exchange.

ABSTRACT: Genetic recombination in bacteriophage lambda relies on DNA end processing by Exo to expose 3'-tailed strands for annealing and exchange by beta protein. Phage lambda encodes an additional recombinase, Orf, which participates in the early stages of recombination by supplying a function equivalent to the Escherichia coli RecFOR complex. These host enzymes assist loading of the RecA strand exchange protein onto ssDNA coated with ssDNA-binding protein. In this study, we purified the Orf protein, analyzed its biochemical properties, and determined its crystal structure at 2.5 angstroms. The homodimeric Orf protein is arranged as a toroid with a shallow U-shaped cleft, lined with basic residues, running perpendicular to the central cavity. Orf binds DNA, favoring single-stranded over duplex and

SUBMITTER: Maxwell KL 

PROVIDER: S-EPMC1183564 | biostudies-literature | 2005 Aug

REPOSITORIES: biostudies-literature