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

D E Cool,C J Edgell,G V Louie,M J Zoller,G D Brayer,R T Macgillivray

doi:10.1016/s0021-9258(17)38776-8

Abstract

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

Highlights

A human liver cDNA library was screened by colony Factor XI1 readily binds to anionic surfaces such as silihybridization with two mixturesof synthetic oligode- cates, dextran sulfate, and sulfatides in vitro
The cDNA sequence predicts that plasma factor XI1 when it comes in contact with collagen or platelet membranes (Wilner et al, 1968;Harpel, 1972).Surface-bound factor XI1 has enzyme activity towards its protein substrates, prekallikrein and factor XI (McMillin et al, 1974;Saito, 1977; Heimark et al, 1980).These two proteins circulate in plasma as inactive zymogens complexed with high molecular weight kininogen
In order to obtain the best overall structural model, the full set of initial atomic coordinatesfor &factor XIIa were further subjected to 10 cycles of structural idealization (final root mean square 6 for bond using this strategy, few random clones were isolated that overlapped the AuaI site of factor XI1 cDNA(Fig. 1).To complete the nucleotide sequence analysis, plasmid pcHXII501 (Fig. 1)was digested with PstI and the 1200- and 280-bp fragments were isolated by polyacrylamide gel electrophoresis

Summary

F X11 TRYP ELAS CHYll tPA I

OTIASN insertions occur at thesurface of the enzyme where there is sufficient more than 90% of the nucleotide sequence was determined room for their placement. In order to obtain the best overall structural model, the full set of initial atomic coordinatesfor &factor XIIa were further subjected to 10 cycles of structural idealization (final root mean square 6 for bond using this strategy, few random clones were isolated that overlapped the AuaI site of factor XI1 cDNA(Fig. 1).To complete the nucleotide sequence analysis, plasmid pcHXII501 (Fig. 1)was digested with PstI and the 1200- and 280-bp fragments were isolated by polyacrylamide gel electrophoresis. Distances, 0.006 A, Konnert and Hendrickson, 1980). It is this final The 280-bp fragment was cloned directly into the PstIsite of predicted model that is discussed

RESULTS

DISCUSSION

Findings

D Kringle Homology: tPA FXI I