National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
R01 HL150146
米国
National Institutes of Health/National Center for Advancing Translational Sciences (NIH/NCATS)
UL1 TR002345
米国
引用
ジャーナル: Blood / 年: 2024 タイトル: Cryo-EM structure and functional basis of prothrombin recognition by a type I antiprothrombin antiphospholipid antibody. 著者: Suresh Kumar / Brock Summers / Kathrine Basore / Vittorio Pengo / Robert Flaumenhaft / Nicola Pozzi / 要旨: Antiprothrombin antibodies are found in antiphospholipid patients, but how they interact with prothrombin remains elusive. Prothrombin adopts closed and open forms. We recently discovered type I and ...Antiprothrombin antibodies are found in antiphospholipid patients, but how they interact with prothrombin remains elusive. Prothrombin adopts closed and open forms. We recently discovered type I and type II antibodies and proposed that type I recognizes the open form. In this study, we report the discovery and structural and functional characterization in human plasma of a type I antibody, POmAb (prothrombin open monoclonal antibody). Using surface plasmon resonance and single-molecule spectroscopy, we show that POmAb interacts with kringle-1 of prothrombin, shifting the equilibrium toward the open form. Using single-particle cryogenic electron microscopy (cryo-EM), we establish that the epitope targeted by POmAb is in kringle-1, comprising an extended binding interface centered at residues R90-Y93. The 3.2-Å cryo-EM structure of the complex reveals that the epitope overlaps with the position occupied by the protease domain of prothrombin in the closed state, explaining the exclusive binding of POmAb to the open form. In human plasma, POmAb prolongs phospholipid-initiated and diluted Russell's viper venom clotting time, which could be partly rescued by excess phospholipids, indicating POmAb is an anticoagulant but exerts a weak lupus anticoagulant effect. These studies reveal the structural basis of prothrombin recognition by a type I antiphospholipid antibody and uncover an exciting new strategy to achieve anticoagulation in human plasma.
全体 : Complex of Fab fragment of POmAb with human prothrombin
全体
名称: Complex of Fab fragment of POmAb with human prothrombin
要素
複合体: Complex of Fab fragment of POmAb with human prothrombin
タンパク質・ペプチド: POmAb Light Chain
タンパク質・ペプチド: POmAb Heavy Chain
タンパク質・ペプチド: Prothrombinトロンビン
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超分子 #1: Complex of Fab fragment of POmAb with human prothrombin
超分子
名称: Complex of Fab fragment of POmAb with human prothrombin タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: all 詳細: Fab fragment generated by proteolytic cleavage of POmAb IgG antibody in complex with open conformation of human prothrombin