Identification and characterization of the WYL BrxR protein and its gene as separable regulatory elements of a BREX phage restriction system.

ABSTRACT: Bacteriophage exclusion ('BREX') phage restriction systems are found in a wide range of bacteria. Various BREX systems encode unique combinations of proteins that usually include a site-specific methyltransferase; none appear to contain a nuclease. Here we describe the identification and characterization of a Type I BREX system from Acinetobacter and the effect of deleting each BREX ORF on growth, methylation, and restriction. We identified a previously uncharacterized gene in the BREX operon that is dispensable for methylation but involved in restriction. Biochemical and crystallographic analyses of this factor, which we term BrxR ('BREX Regulator'), demonstrate that it forms a homodimer and specifically binds a DNA target site upstream of its transcription start site. Deletion of the Brx

SUBMITTER: Luyten YA 

PROVIDER: S-EPMC9122589 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature