Oma1 peptidase-like, integral membrane metallopeptidase
This family contains peptidase M48 subfamily C (also known as Oma1 peptidase or mitochondrial metalloendopeptidase OMA1), including similar peptidases containing tetratricopeptide (TPR) repeats, as well as uncharacterized proteins such as E. coli bepA (formerly yfgC), ycaL and loiP (formerly yggG), considered to be putative metallopeptidases. Oma1 peptidase is part of the quality control system in the inner membrane of mitochondria, with its catalytic site facing the matrix space. It cleaves and thereby promotes the turnover of mistranslated or misfolded membrane proteins. Oma1 can cleave the misfolded multi-pass membrane protein Oxa1, thus exerting a function similar to the ATP-dependent m-AAA protease for quality control of inner membrane proteins. It has been proposed that in the absence of m-AAA protease, proteolysis of Oxa1 is mediated by Oma1 in an ATP-independent manner. Homologs of Oma1 are present in higher eukaryotes, eubacteria and archaebacteria, suggesting that Oma1 is the founding member of a conserved family of membrane-embedded metallopeptidases, all containing the zinc metalloprotease motif (HEXXH). M48 peptidases proteolytically remove the C-terminal three residues of farnesylated proteins.