Transposon-mediated linker insertion scanning mutagenesis of the Escherichia coli McrA endonuclease.

ABSTRACT: McrA is one of three functions that restrict modified foreign DNA in Escherichia coli K-12, affecting both methylated and hydroxymethylated substrates. We present here the first systematic analysis of the functional organization of McrA by using the GPS-LS insertion scanning system. We collected in-frame insertions of five amino acids at 46 independent locations and C-terminal truncations at 20 independent locations in the McrA protein. Each mutant was assayed for in vivo restriction of both methylated and hydroxymethylated bacteriophage (M.HpaII-modified lambda and T4gt, respectively) and for induction of the E. coli SOS response in the presence of M.HpaII methylation, indicative of DNA damage. Our findings suggest the presence of an N-terminal DNA-binding domain and a C-terminal catalyti

SUBMITTER: Anton BP 

PROVIDER: S-EPMC516834 | biostudies-literature | 2004 Sep

REPOSITORIES: biostudies-literature