Rapid and ordered cleavage of prothrombin by Hopsarin D in the absence of phospholipid membranes.

Item request has been placed! ×
Item request cannot be made. ×
loading   Processing Request
Read More Add to Saved list
  • Additional Information
    • Source:
      Publisher: Elsevier Country of Publication: England NLM ID: 101170508 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1538-7836 (Electronic) Linking ISSN: 15387836 NLM ISO Abbreviation: J Thromb Haemost Subsets: MEDLINE
    • Publication Information:
      Publication: 2023- : [New York] : Elsevier
      Original Publication: Oxford : Blackwell Pub.
    • Subject Terms:
      Prothrombin*/metabolism ; Phospholipids*/metabolism ; Blood Coagulation* ; Protein Binding* ; Factor Xa*/metabolism ; Thrombin*/metabolism ; Thrombin*/chemistry; Humans ; Animals ; Elapid Venoms/metabolism ; Elapid Venoms/chemistry ; Enzyme Precursors/metabolism ; Kinetics ; Factor V/metabolism
    • Abstract:
      Background: Thrombin is produced by the prothrombinase complex, composed of factor (f)Xa and fVa on a phospholipid (PL) membrane surface. Snakes of the Elapidae family have venom versions of these factors that cause coagulopathy in prey. Group C venoms contain both fⅩa and fⅤa orthologues. Group D venoms only contain a fXa orthologue and hijack fⅤa of the prey. Hopsarin D (HopD) is the venom fⅩa of the Stephen's banded snake (Hoplocephalus stephensii).
      Objectives: We set out to address the following: does HopD bind to human fⅤa with high affinity in the absence of PL? Does it process prothrombin through the meizothrombin pathway? Is the order of cleavage PL-dependent? Can HopD activate fⅤ?
      Methods: We produced and characterized full-length and truncated HopD.
      Results: HopD is only able to clot plasma that contains fⅤ and competes with human fⅩa for fⅤa binding. HopD binds to both human fⅤa and fⅤ with high affinity (dissociation constant, ∼10 nM), in contrast to fⅩa. HopD processes prothrombin down the meizothrombin route in the absence and presence of PL. Although HopD can bind to fⅤ, conversion to fⅤa is necessary for prothrombin processing. HopD initiates clotting in the blood of prey by activating fⅤ.
      Conclusion: HopD binds to fⅤa with high affinity and rapidly activates prothrombin in the absence of PL, exclusively through the meizothrombin intermediate. HopD binds with high affinity to both fⅤa and fⅤ, suggesting that the B-domain does not sterically block fⅩa binding, but inhibits productive interaction in another way, and additionally prevents prothrombin binding.
      Competing Interests: Declaration of competing interests There are no competing interests to disclose.
      (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)
    • Contributed Indexing:
      Keywords: blood coagulation; hemostasis; thrombin; thrombosis; venom
    • Accession Number:
      9001-26-7 (Prothrombin)
      0 (Phospholipids)
      EC 3.4.21.6 (Factor Xa)
      EC 3.4.21.5 (Thrombin)
      0 (Elapid Venoms)
      EC 3.4.21.5 (meizothrombin)
      0 (Enzyme Precursors)
      0 (prothrombinase complex)
      9001-24-5 (Factor V)
    • Publication Date:
      Date Created: 20240816 Date Completed: 20241026 Latest Revision: 20241104
    • Publication Date:
      20241104
    • Accession Number:
      10.1016/j.jtha.2024.07.027
    • Accession Number:
      39151702