Symbol Cementoin InterPro IPR019541 PDB RCSB PDB; PDBe; PDBj | Pfam PF10511 Pfam structures PDBsum structure summary | |
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In molecular biology, the trappin protein transglutaminase binding domain or cementoin is a protein domain found at the N-terminus of Whey Acidic Protein (WAP) domain-containing protease inhibitors such as trappin-2. This N-terminal domain enables it to become cross-linked to extracellular matrix proteins by transglutaminase. This domain contains several repeated motifs with the consensus sequence Gly-Gln-Asp-Pro-Val-Lys, and these together can anchor the whole molecule to extracellular matrix proteins, such as laminin, fibronectin, beta-crystallin, collagen IV, fibrinogen, and elastin, by transglutaminase-catalysed cross-links. The whole domain is rich in glutamine and lysine, thus allowing transglutaminase(s) to catalyse the formation of an intermolecular epsilon-(gamma-glutamyl)lysine isopeptide bond.