Analysis of Escherichia coli RecA interactions with LexA, lambda CI, and UmuD by site-directed mutagenesis of recA.

ABSTRACT: An early event in the induction of the SOS system of Escherichia coli is RecA-mediated cleavage of the LexA repressor. RecA acts indirectly as a coprotease to stimulate repressor self-cleavage, presumably by forming a complex with LexA. How complex formation leads to cleavage is not known. As an approach to this question, it would be desirable to identify the protein-protein interaction sites on each protein. It was previously proposed that LexA and other cleavable substrates, such as phage lambda CI repressor and E. coli UmuD, bind to a cleft located between two RecA monomers in the crystal structure. To test this model, and to map the interface between RecA and its substrates, we carried out alanine-scanning mutagenesis of RecA. Twenty double mutations were made, and cells carrying them

SUBMITTER: Mustard JA 

PROVIDER: S-EPMC94464 | biostudies-literature | 2000 Mar

REPOSITORIES: biostudies-literature