Characterization of human blood coagulation factor XII cDNA. Prediction of the primary structure of factor XII and the tertiary structure of beta-factor XIIa.

摘要: A human liver cDNA library was screened by colony hybridization with two mixtures of synthetic oligodeoxyribonucleotides as probes. These oligonucleotides encoded regions beta-factor XIIa predicted from the amino acid sequence. Four positive clones were isolated that contained DNA coding for most factor XII mRNA. sequence analysis these overlapping showed they part an amino-terminal extension, complete plasma XII, a TGA stop codon, 3' untranslated region 150 nucleotides, and poly(A)+ tail. The predicts consists 596 residues. Within we have identified three peptide bonds are cleaved kallikrein during formation XIIa. Comparison structure other proteins revealed extensive identity tissue-type plasminogen activator (the epidermal growth factor-like kringle region) fibronectin (type I type II homologies). As contains collagen-binding site, homologous in may be responsible binding to collagen. carboxyl-terminal shares considerable homology serine proteases including trypsin many clotting factors. preliminary structural model is proposed based on known high resolution x-ray diffraction structures trypsin, chymotrypsin, elastase.