RRC ID 71454
Author Nashimoto Y, Matsushita F, Dijkstra JM, Nakamura Y, Akiyama H, Hamako J, Morita T, Araki S, Matsui T.
Title Bitiscetin-3, a Novel C-Type Lectin-like Protein Cloned from the Venom Gland of the Viper Bitis arietans, Induces Platelet Agglutination and Inhibits Binding of Von Willebrand Factor to Collagen.
Journal Toxins (Basel)
Abstract Bitiscetin-1 (aka bitiscetin) and bitiscetin-2 are C-type lectin-like proteins purified from the venom of Bitis arietans (puff adder). They bind to von Willebrand factor (VWF) and-at least bitiscetin-1-induce platelet agglutination via enhancement of VWF binding to platelet glycoprotein Ib (GPIb). Bitiscetin-1 and -2 bind the VWF A1 and A3 domains, respectively. The A3 domain includes the major site of VWF for binding collagen, explaining why bitiscetin-2 blocks VWF-to-collagen binding. In the present study, sequences for a novel bitiscetin protein-bitiscetin-3-were identified in cDNA constructed from the B. arietans venom gland. The deduced amino acid sequences of bitiscetin-3 subunits α and β share 79 and 80% identity with those of bitiscetin-1, respectively. Expression vectors for bitiscetin-3α and -3β were co-transfected to 293T cells, producing the heterodimer protein recombinant bitiscetin-3 (rBit-3). Functionally, purified rBit-3 (1) induced platelet agglutination involving VWF and GPIb, (2) did not compete with bitiscetin-1 for binding to VWF, (3) blocked VWF-to-collagen binding, and (4) lost its platelet agglutination inducing ability in the presence of an anti-VWF monoclonal antibody that blocked VWF-to-collagen binding. These combined results suggest that bitiscetin-3 binds to the A3 domain, as does bitiscetin-2. Except for a small N-terminal fragment of a single subunit-which differs from that of both bitiscetin-3 subunits-the sequences of bitiscetin-2 have never been determined. Therefore, by identifying and analyzing bitiscetin-3, the present study is the first to present the full-length α- and β-subunit sequences and recombinant expression of a bitiscetin-family toxin that blocks the binding of VWF to collagen.
Volume 14(4)
Published 2022-3-25
DOI 10.3390/toxins14040236
PII toxins14040236
PMID 35448845
PMC PMC9024624
MeSH Agglutination Animals Binding Sites Blood Platelets / metabolism Collagen / metabolism Lectins, C-Type / genetics Lectins, C-Type / metabolism Peptides / pharmacology Platelet Glycoprotein GPIb-IX Complex / metabolism Protein Binding Snake Venoms Viperidae* / metabolism von Willebrand Factor* / metabolism
IF 3.531
Human and Animal Cells 293T(RCB2202)