cd03869: M14_CPX_like (this model, PSSM-Id:199851 is obsolete and has been replaced by 349441)
Peptidase M14 carboxypeptidase subfamily N/E-like; Carboxypeptidase X subgroup
Peptidase M14-like domain of carboxypeptidase (CP)-like protein X (CPX), CPX forms a distinct subgroup of the N/E subfamily of the M14 family of metallocarboxypeptidases (MCPs). The M14 family are zinc-binding 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. Proteins belonging to this subgroup include CP-like protein X1 (CPX1), CP-like protein X2 (CPX2), and aortic CP-like protein (ACLP) and its isoform adipocyte enhancer binding protein-1 (AEBP1). AEBP1 is a truncated form of ACLP, which may arise from alternative splicing of the gene. These proteins are inactive towards standard CP substrates because they lack one or more critical active site and substrate-binding residues that are necessary for activity. They may function as binding proteins rather than as active CPs or display catalytic activity toward other substrates. Proteins in this subgroup also contain an N-terminal discoidin domain. The CP domain is important for the function of AEBP1 as a transcriptional repressor. AEBP1 is involved in several biological processes including adipogenesis, macrophage cholesterol homeostasis, and inflammation. In macrophages, AEBP1 promotes the expression of IL-6, TNF-alpha, MCP-1, and iNOS whose expression is tightly regulated by NF-kappaB activity. ACLP, a secreted protein that associates with the extracellular matrix, is essential for abdominal wall development and contributes to dermal wound healing.
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.
Jiyao W et al.(2023). "The conserved domain database in 2023.",