|Chromosome||Unplaced: 29.75 - 29.79 Mb|
Draculin (named after Count Dracula) is a glycoprotein found in the saliva of vampire bats. It is composed of 708 amino acids, weighing about 76,9 kDa. It functions as an anticoagulant, inhibiting coagulation factors IX (IXa) and X (Xa), thus keeping the blood of the bitten victim from clotting while the bat is drinking. Draculin is a member of the lactotransferrin family of proteins that functions an antibacterial protein in other mammals, but has been co-opted in bat evolution to function as an anticoagulant.
Draculin is a reversible, slow tight binding, noncompetitive inhibitor of FXa. It does not act on thrombin, trypsin or chymotrypsin and does not express fibrinolytic activity. The protein increases the lag phase as well as the height of the peak of thrombin generation when in plasma, leading to prolonged bleeding.
Daily salivation of vampire bats yields a saliva that progressively decreases in anticoagulant activity. However, there is no significant change in overall protein content during this time. After a 4-day period of rest, anticoagulant activity of the saliva is restored. In addition, purified native draculin, obtained from high- and low-activity saliva, shows significant differences in composition of the carbohydrate moiety, and glycosylation pattern. Furthermore, controlled chemical deglycosylation of native draculin progressively leads to complete loss of the biological activity, despite the conditions leaving the polypeptide backbone intact.
- Low DH, Sunagar K, Undheim EA, Ali SA, Alagon AC, Ruder T, Jackson TN, Pineda Gonzalez S, King GF, Jones A, Antunes A, Fry BG (August 2013). "Dracula's children: molecular evolution of vampire bat venom". Journal of Proteomics. 89: 95–111. doi:10.1016/j.jprot.2013.05.034. PMID 23748026.
- Fernandez AZ, Tablante A, Beguín S, Hemker HC, Apitz-Castro R (September 1999). "Draculin, the anticoagulant factor in vampire bat saliva, is a tight-binding, noncompetitive inhibitor of activated factor X". Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology. 1434 (1): 135–42. doi:10.1016/s0167-4838(99)00160-0. PMID 10556567.
- Fernandez AZ, Tablante A, Bartoli F, Beguin S, Hemker HC, Apitz-Castro R (October 1998). "Expression of biological activity of draculin, the anticoagulant factor from vampire bat saliva, is strictly dependent on the appropriate glycosylation of the native molecule" (PDF). Biochimica et Biophysica Acta (BBA) - General Subjects. 1425 (2): 291–9. doi:10.1016/s0304-4165(98)00082-8. PMID 9795244.
- Apitz-Castro R, Béguin S, Tablante A, Bartoli F, Holt JC, Hemker HC (January 1995). "Purification and partial characterization of draculin, the anticoagulant factor present in the saliva of vampire bats (Desmodus rotundus)". Thrombosis and Haemostasis. 73 (1): 94–100. doi:10.1055/s-0038-1653731. PMID 7740503.