Probable endoribonuclease HigB1

UniProtKB accession:  P9WJA5

Grouped By:  Matching UniProtKB accession

UniProtKB description:  Toxic component of an atypical, type II toxin-antitoxin chaperone (TAC) system. Upon expression in M.smegmatis inhibits colony formation and cell growth (PubMed:20011113, PubMed:23927792). Ectopic expression in wild-type M.tuberculosis has no effect on cell growth; ectopic expression in a triple higB1-higA1-Rv1957 (delta TAC) disruption mutant causes growth arrest, killing a considerable proportion of the cells. Increased ectopic expression leads to decreased levels of IdeR- and Zur-regulated genes as well as cleavage within the mRNA region of tmRNA (transfer-mRNA), strongly suggesting it is an endoribonuclease; also degrades E.coli and M-smegmatis tmRNA (PubMed:23927792). Its toxic effect is neutralized by coexpression with antitoxin HigA. Neutralization of HigB1 toxin in E.coli or M.marinum also requires SecB-like chaperone Rv1957, making this the first toxin-antitoxin chaperone (TAC) system (PubMed:21536872).