Enhanced Local Disorder in a Clinically Elusive von Willebrand Factor Provokes High-Affinity Platelet Clumping
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Enhanced Local Disorder in a Clinically Elusive von Willebrand Factor Provokes High-Affinity Platelet Clumping. / Tischer, Alexander; Machha, Venkata R; Frontroth, Juan P; Brehm, Maria A; Obser, Tobias; Schneppenheim, Reinhard; Mayne, Leland; Walter Englander, S; Auton, Matthew.
In: J MOL BIOL, Vol. 429, No. 14, 07.07.2017, p. 2161-2177.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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TY - JOUR
T1 - Enhanced Local Disorder in a Clinically Elusive von Willebrand Factor Provokes High-Affinity Platelet Clumping
AU - Tischer, Alexander
AU - Machha, Venkata R
AU - Frontroth, Juan P
AU - Brehm, Maria A
AU - Obser, Tobias
AU - Schneppenheim, Reinhard
AU - Mayne, Leland
AU - Walter Englander, S
AU - Auton, Matthew
N1 - Copyright © 2017 Elsevier Ltd. All rights reserved.
PY - 2017/7/7
Y1 - 2017/7/7
N2 - Mutation of the cysteines forming the disulfide loop of the platelet GPIbα adhesive A1 domain of von Willebrand factor (VWF) causes quantitative VWF deficiencies in the blood and von Willebrand disease. We report two cases of transient severe thrombocytopenia induced by DDAVP treatment. Cys1272Trp and Cys1458Tyr mutations identified by genetic sequencing implicate an abnormal gain-of-function phenotype, evidenced by thrombocytopenia, which quickly relapses back to normal platelet counts and deficient plasma VWF. Using surface plasmon resonance, analytical rheology, and hydrogen-deuterium exchange mass spectrometry (HXMS), we decipher mechanisms of A1-GPIbα-mediated platelet adhesion and resolve dynamic secondary structure elements that regulate the binding pathway. Constrained by the disulfide, conformational selection between weak and tight binding states of A1 takes precedence and drives normal platelet adhesion to VWF. Less restrained through mutation, loss of the disulfide preferentially diverts binding through an induced-fit disease pathway enabling high-affinity GPIbα binding and firm platelet adhesion to a partially disordered A1 domain. HXMS reveals a dynamic asymmetry of flexible and ordered regions common to both variants, indicating that the partially disordered A1 lacking the disulfide retains native-like structural dynamics. Both binding mechanisms share common structural and thermodynamic properties, but the enhanced local disorder in the disease state perpetuates high-affinity platelet agglutination, characteristic of type 2B VWD, upon DDAVP-stimulated secretion of VWF leading to transient thrombocytopenia and a subsequent deficiency of plasma VWF, characteristic of type 2A VWD.
AB - Mutation of the cysteines forming the disulfide loop of the platelet GPIbα adhesive A1 domain of von Willebrand factor (VWF) causes quantitative VWF deficiencies in the blood and von Willebrand disease. We report two cases of transient severe thrombocytopenia induced by DDAVP treatment. Cys1272Trp and Cys1458Tyr mutations identified by genetic sequencing implicate an abnormal gain-of-function phenotype, evidenced by thrombocytopenia, which quickly relapses back to normal platelet counts and deficient plasma VWF. Using surface plasmon resonance, analytical rheology, and hydrogen-deuterium exchange mass spectrometry (HXMS), we decipher mechanisms of A1-GPIbα-mediated platelet adhesion and resolve dynamic secondary structure elements that regulate the binding pathway. Constrained by the disulfide, conformational selection between weak and tight binding states of A1 takes precedence and drives normal platelet adhesion to VWF. Less restrained through mutation, loss of the disulfide preferentially diverts binding through an induced-fit disease pathway enabling high-affinity GPIbα binding and firm platelet adhesion to a partially disordered A1 domain. HXMS reveals a dynamic asymmetry of flexible and ordered regions common to both variants, indicating that the partially disordered A1 lacking the disulfide retains native-like structural dynamics. Both binding mechanisms share common structural and thermodynamic properties, but the enhanced local disorder in the disease state perpetuates high-affinity platelet agglutination, characteristic of type 2B VWD, upon DDAVP-stimulated secretion of VWF leading to transient thrombocytopenia and a subsequent deficiency of plasma VWF, characteristic of type 2A VWD.
KW - Amino Acid Substitution
KW - Child
KW - Cysteine
KW - Deamino Arginine Vasopressin
KW - Disulfides
KW - Female
KW - Humans
KW - Mass Spectrometry
KW - Mutant Proteins
KW - Mutation, Missense
KW - Platelet Aggregation
KW - Platelet Glycoprotein GPIb-IX Complex
KW - Plethysmography, Impedance
KW - Surface Plasmon Resonance
KW - Thrombocytopenia
KW - von Willebrand Factor
KW - Case Reports
KW - Journal Article
U2 - 10.1016/j.jmb.2017.05.013
DO - 10.1016/j.jmb.2017.05.013
M3 - SCORING: Journal article
C2 - 28533135
VL - 429
SP - 2161
EP - 2177
JO - J MOL BIOL
JF - J MOL BIOL
SN - 0022-2836
IS - 14
ER -