Analysis of the partial nucleotide sequences and deduced primary structures of the protease domains of mammalian blood coagulation factors VII and X.

In order to obtain sequence data for the blood coagulation factor VII and factor X in several mammalian species, we amplified and sequenced the DNA segments of exon VIII from each gene by means of the polymerase chain reaction (PCR) method. The DNA segments from the following species were successfully amplified: factor VII from the rhesus monkey and dog, and factor X from the rhesus monkey, Syrian hamster and rat. In each factor, the nucleotide sequences and predicted primary structures of the protease domain showed a high degree of homology among species; amino acid identities of approximately 68%-92% and 80%-98% were demonstrated among species in factor VII and factor X, respectively. The locations of the active site residues and five Cys residues were evolutionarily conserved in both factors. Interestingly, the amino acids involved in the human genetic variants, both factor VII 304-Arg and factor X 326-Arg, were always conserved across species. The data presented here will be helpful for investigating human genetic variants of factor VII or X, and will provide considerable information for constructing in vitro site-specific mutants of these factors.