Peptidase M14-like domain of ATP/GTP binding proteins and cytosolic carboxypeptidases; uncharacterized bacterial subgroup
A bacterial subgroup of the Peptidase M14-like domain of Nna-1 (Nervous system Nuclear protein induced by Axotomy), also known as ATP/GTP binding protein (AGTPBP-1) and cytosolic carboxypeptidase (CCP),-like proteins. The Peptidase M14 family of metallocarboxypeptidases are zinc-binding carboxypeptidases (CPs) which hydrolyze single, C-terminal amino acids from polypeptide chains, and have a recognition site for the free C-terminal carboxyl group, which is a key determinant of specificity. Nna1-like proteins are active metallopeptidases that are thought to act on cytosolic proteins (such as alpha-tubulin in eukaryotes) to remove a C-terminal tyrosine. Nna1-like proteins from the different phyla are highly diverse, but they all contain a unique N-terminal conserved domain right before the CP domain. It has been suggested that this N-terminal domain might act as a folding domain.
Comment:Metallocarboxypeptidases share the zinc binding motif HXXE...H, where the zinc ion is penta-coordinated to ND1 atoms of the histidines, OE1 and OE2 atoms of the glutamic acid, and to a water molecule in a slightly distorted tetrahedral manner.
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