Lessons from snake venom: new insights into the structural and functional aspects of factor V and factor X

Verhoef, D. (2021)

Doctoral Thesis

The venom of the Australian snake Pseudonaja textilis contains coagulation factors V (five) and X (ten) which have been adapted to derail the blood clotting system of its prey. Snake venom factor V is unique in that is constitutively active, unlike its human counterpart. The snake liver transcriptome was found to contain alternatively spliced factor V mRNA that encoded for either the activated protein or its quiescent form. A potential pre-mRNA splicing mechanism was uncovered that may yield the active protein. Snake venom factor V is also particularly stable due to several modifications to its molecular structure. These modifications have been investigated in detail by engineering chimeras of human and snake venom factor V. The snake venom factor X molecule was also investigated in more detail. It was discovered that this enzyme is insensitive to the action of certain anticoagulant drugs (Factor Xa inhibitors) due to a unique molecular modification. A Human factor X can be modified in similar fashion, so that it is no longer sensitive to the action of Factor Xa inhibitors. This finding could make an important contribution to acute care for patients who experience life-threatening bleeding after the use of FXa inhibitors.

• Blood coagulation
• Snake venom
• Biochemistry
• Coagulation factor V
• Coagulation factor X
• Protein engineering
• Biophysical assays
• Enzymatic inhibitors
• Clotting assays
• Thrombin generation

• All authors: Verhoef, D.
• Supervisor: Reitsma, P.H.
• Co-supervisor: Bos, M.H.A.
• Committee: Versteeg, H.H.; Meijer, A.B.; Castoldi, E.
• Qualification: Doctor (dr.)
• Awarding Institution: Faculty of Medicine, Leiden University Medical Center [LUMC], Leiden University
• Date: 2021-09-22
• ISBN (print): 9789464166002
• Sponsorship: The research described in this thesis was funded by the European Union FP7 People Program, the National Blood Foundation, the Trombosestichting Nederland and the Bayer Hemophilia Awards Program. The research was performed at the Einthoven Laboratory for Vascular and Regenerative Medicine of the Leiden University Medical Center, Leiden, The Netherlands. Financial support by VarmX. B.V. for the publication of this thesis is gratefully acknowledged.