scholarly journals The von Willebrand factor-binding domain of platelet membrane glycoprotein Ib. Characterization by monoclonal antibodies and partial amino acid sequence analysis of proteolytic fragments.

1986 ◽  
Vol 261 (27) ◽  
pp. 12579-12585 ◽  
Author(s):  
M Handa ◽  
K Titani ◽  
L Z Holland ◽  
J R Roberts ◽  
Z M Ruggeri
Keyword(s):  
Monoclonal Antibodies ◽  
Amino Acid ◽  
Sequence Analysis ◽  
Amino Acid Sequence ◽  
Von Willebrand Factor ◽  
Membrane Glycoprotein ◽  
Amino Acid Sequence Analysis ◽  
Partial Amino Acid Sequence ◽  
Von Willebrand ◽  
Willebrand Factor

scholarly journals The von willebrand factor domain-mediating botrocetin-induced binding to glycoprotein IB lies between Val449 and Lys728

Blood ◽  
1987 ◽  
Vol 70 (4) ◽  
pp. 985-988 ◽  
Author(s):  
Y Fujimura ◽  
LZ Holland ◽  
ZM Ruggeri ◽  
TS Zimmerman
Keyword(s):  
Monoclonal Antibodies ◽  
Amino Acid ◽  
Von Willebrand Factor ◽  
Amino Acid Residue ◽  
Von Willebrand Disease ◽  
Platelet Glycoprotein ◽  
Tryptic Fragment ◽  
Alternative Agent ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Botrocetin, a component of Bothrops jararaca venom, induces von Willebrand factor (vWF)-dependent platelet agglutination and has been proposed as an alternative agent to ristocetin for evaluating vWF function. However, important differences between the vWF-platelet interactions induced by these two agents have suggested that different regions of vWF and the platelet may be involved in the interactions induced by the two agonists. We have recently demonstrated that binding of vWF to the platelet glycoprotein (GP) Ib receptor, either induced by ristocetin or as occurs spontaneously with asialo-vWF or vWF from IIb von Willebrand disease, is mediated by a domain residing on a 52/48- kilodalton (kD) tryptic fragment of vWF. This fragment extends from amino acid residue Val (449) to Lys (728). We have now found that this 52/48-kD fragment blocks botrocetin-induced binding of vWF to platelets and completely inhibits botrocetin-induced platelet agglutination. These results provide evidence that the vWF domain-mediating, botrocetin-induced platelet agglutination lies within the region delimited by this fragment and is therefore close to or identical with that which mediates ristocetin-induced binding and spontaneous binding of vWF to platelet GPIb. Anti-GPIb monoclonal antibodies also blocked agglutination, which showed that botrocetin, like ristocetin, induces binding of vWF to the GPIb receptor.

Structure and function of the von Willebrand factor A1 domain: analysis with monoclonal antibodies reveals distinct binding sites involved in recognition of the platelet membrane glycoprotein Ib-IX-V complex and ristocetin-dependent activation

Blood ◽  
2000 ◽  
Vol 95 (1) ◽  
pp. 164-172 ◽  
Author(s):  
Mariagrazia De Luca ◽  
David A. Facey ◽  
Emmanuel J. Favaloro ◽  
Mark S. Hertzberg ◽  
James C. Whisstock ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Platelet Aggregation ◽  
Von Willebrand Factor ◽  
Platelet Membrane ◽  
Membrane Glycoprotein ◽  
Platelet Membrane Glycoprotein ◽  
And Function ◽  
A1 Domain ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Binding of the adhesive glycoprotein, von Willebrand factor (vWf), to the platelet membrane glycoprotein (GP) Ib-IX-V complex initiates platelet adhesion and aggregation at high shear stress in hemostasis and thrombosis. In this study, the GP Ib-IX-V binding site within the vWf A1 domain was analyzed using a panel of murine monoclonal antibodies raised against a 39/34-kd vWf fragment (Leu-480/Val-481–Gly-718) encompassing the A1 domain. One antibody, 6G1, strongly inhibited ristocetin-dependent vWf binding to platelets, but had no effect on botrocetin- or jaracetin-dependent binding, or asialo-vWf–dependent platelet aggregation. The 6G1 epitope was mapped to Glu-700–Asp-709, confirming the importance of this region for modulation of vWf by ristocetin. Like ristocetin, 6G1 activated the vWf A1 domain, because it enhanced binding of the 39/34-kd fragment to platelets. In contrast, 5D2 and CR1 completely inhibited asialo-vWf–induced platelet aggregation and ristocetin-induced vWf binding to GP Ib-IX-V. However, only 5D2 blocked botrocetin- and jaracetin-induced vWf binding to platelets and binding of vWf to botrocetin- and jaracetin-coated beads. Epitopes for 5D2 and CR1 were conformationally dependent, but not congruent. Other antibodies mapped to epitopes within the A1 domain (CR2 and CR15, Leu-494–Leu-512; CR2, Phe-536–Ala-554; CR3, Arg-578–Glu-596; CR11 and CR15, Ala-564–Ser-582) were not functional, identifying regions of the vWf A1 domain not directly involved in vWf-GP Ib-IX-V interaction. The combined results provide evidence that the proline-rich sequence Glu-700–Asp-709 constitutes a regulatory site for ristocetin, and that ristocetin and botrocetin induce, at least in part, separate receptor-recognition sites on vWf. (Blood. 2000;95:164-172)

Partial amino acid sequence of purified von Willebrand factor–cleaving protease

Blood ◽  
2001 ◽  
Vol 98 (6) ◽  
pp. 1654-1661 ◽  
Author(s):  
Helena E. Gerritsen ◽  
Rodolfo Robles ◽  
Bernhard Lämmle ◽  
Miha Furlan
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Affinity Chromatography ◽  
Human Plasma ◽  
Von Willebrand Factor ◽  
Normal Human Plasma ◽  
High Molecular Weight Complex ◽  
Normal Human ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract von Willebrand factor–cleaving protease (vWF-cp) is responsible for the continuous degradation of plasma vWF multimers released from endothelial cells. It is deficient in patients with thrombotic thrombocytopenic purpura, who show unusually large vWF multimers in plasma. Purified vWF-cp may be useful for replacement in these patients, who are now treated by plasma therapy. In this study, vWF-cp was purified from normal human plasma by affinity chromatography on the IgG fraction from a patient with autoantibodies to vWF-cp and by a series of further chromatographic procedures, including affinity chromatography on Protein G, Ig-TheraSorb, lentil lectin, and heparin. Four single-chain protein bands, separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions, showed Mr of 150, 140, 130, and 110 kd and were found to share the same N-terminal amino acid sequence, suggesting that they were derived from the same polypeptide chain that had been partially degraded at the carboxy-terminal end. A hydrophobic sequence (Ala-Ala-Gly-Gly-Ile-Leu-His-Leu-Glu-Leu-Leu-Val-Ala-Val-Gly) of the first 15 residues was established. The protease migrates in gel filtration as a high-molecular-weight complex with clusterin, a 70-kd protein with chaperonelike activity. vWF-cp bound to clusterin is dissociated by the use of concentrated chaotropic salts. vWF-cp in normal human plasma or serum is not associated with clusterin, suggesting that the observed complex is due to vWF-cp denaturation during the purification procedure. Activity of vWF-cp is unusually stable during incubation at 37°C; its in vitro half-life in citrated human plasma, heparin plasma, or serum is longer than 1 week. There was even a temporary increase in protease activity during the first 3 days of incubation.

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