Host-nuclease inhibitor protein gam

UniProtKB accession:  P03702

Grouped By:  Matching UniProtKB accession

UniProtKB description:  Both GamL and GamS bind to host RecBCD nuclease and inhibit its activities, protecting the viral DNA against RecBCD mediated degradation (PubMed:2943636, PubMed:4275917, PubMed:126236, PubMed:1653221, PubMed:17544443). Isoform GamS mimics DNA, preventing RecBCD from binding DNA (PubMed:17544443, PubMed:28009252). Expression of this protein in E.coli renders cells more sensitive to fluoroquinolone antibiotics (which inhibit topoisomerases and induce dsDNA breaks) (PubMed:28009252). Frameshift mutations that delete most of this protein (starting from position 78 or 97 of GamL) allow the bacteriophage to overcome the retron Ec48 bacteriophage defense system. Overexpression of the wild-type gam protein in E.coli with an intact Ec48 retron leads to a dramatic decrease in cell growth, the frameshift mutants do not have this effect (PubMed:33157039).