From Proteopediaproteopedia link
THREE-DIMENSIONAL STRUCTURE OF A TRANSGLUTAMINASE: HUMAN BLOOD COAGULATION FACTOR XIII
[F13A_HUMAN] Defects in F13A1 are the cause of factor XIII subunit A deficiency (FA13AD) [MIM:613225]. FA13AD is an autosomal recessive disorder characterized by a life-long bleeding tendency, impaired wound healing and spontaneous abortion in affected women.
[F13A_HUMAN] Factor XIII is activated by thrombin and calcium ion to a transglutaminase that catalyzes the formation of gamma-glutamyl-epsilon-lysine cross-links between fibrin chains, thus stabilizing the fibrin clot. Also cross-link alpha-2-plasmin inhibitor, or fibronectin, to the alpha chains of fibrin.
Publication Abstract from PubMed
Mechanical stability in many biological materials is provided by the crosslinking of large structural proteins with gamma-glutamyl-epsilon-lysyl amide bonds. The three-dimensional structure of human recombinant factor XIII (EC 184.108.40.206 zymogen; protein-glutamine:amine gamma-glutamyltransferase a chain), a transglutaminase zymogen, has been solved at 2.8-A resolution by x-ray crystallography. This structure shows that each chain of the homodimeric protein is folded into four sequential domains. A catalytic triad reminiscent of that observed in cysteine proteases has been identified in the core domain. The amino-terminal activation peptide of each subunit crosses the dimer interface and partially occludes the opening of the catalytic cavity in the second subunit, preventing substrate binding to the zymogen. A proposal for the mechanism of activation by thrombin and calcium is made that details the structural events leading to active factor XIIIa'.
Three-dimensional structure of a transglutaminase: human blood coagulation factor XIII.,Yee VC, Pedersen LC, Le Trong I, Bishop PD, Stenkamp RE, Teller DC Proc Natl Acad Sci U S A. 1994 Jul 19;91(15):7296-300. PMID:7913750
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.