Thromb Haemost 2004; 92(03): 509-521
DOI: 10.1160/TH04-03-0144
Blood Coagulation, Fibrinolysis and Cellular Haemostasis
Schattauer GmbH

The catalytic subunit of pseutarin C, a group C prothrombin activator from the venom of Pseudonaja textilis, is structurally similar to mammalian blood coagulation factor Xa

Veena S. Rao
1   Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Republic of Singapore
,
Sanjay Swarup
1   Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Republic of Singapore
,
Manjunatha R. Kini
1   Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Republic of Singapore
2   Department of Biochemistry, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia, USA
› Institutsangaben

Financial support: This work was supported by Academic Research Fund from the National University of Singapore.
Weitere Informationen

Publikationsverlauf

Received 07. März 2004

Accepted after resubmission 10. Juni 2004

Publikationsdatum:
30. November 2017 (online)

Preview

Summary

Pseutarin C, a group C prothrombin activator from Pseudonaja textilis venom, is a large protein complex consisting of catalytic and nonenzymatic subunits, which are functionally similar to the mammalian FXa-FVa complex. Here, we present the complete cDNA sequence of the catalytic subunit of pseutarin C. The cDNA of the catalytic subunit encodes a protein of 449 amino acids, which includes a 22-residue signal peptide, 18-residue propeptide and a mature protein of 409 amino acids. The deduced amino acid sequence shows 74-83% identity to group D prothrombin activators from snake venom and ∼42% identity to mammalian FX and has identical domain structure. The precursor of the catalytic subunit of pseutarin C has several unique features. The activation peptide of the catalytic subunit of pseutarin C is significantly smaller (27 as compared to 52 residues in mammalian FX) and does not contain any glycosylation sites. Unlike coagulation FXa, Ser52 and Asn45 of the light and heavy chains are O- and N-glycosylated in pseutarin C catalytic subunit. There is a 12-residue insertion in pseutarin C catalytic subunit close to the region that is implicated in binding to FVa. This is the first sequence of the catalytic subunit of a group C prothrombin activator.