National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
R35 HL135823
米国
National Institutes of Health/National Heart, Lung, and Blood Institute (NIH/NHLBI)
R35 HL171334
米国
National Institutes of Health/Office of the Director
S10OD030275
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R24 GM145965
米国
American Heart Association
N028347
米国
引用
ジャーナル: Blood / 年: 2025 タイトル: Cryo-EM structure of the tissue factor/factor VIIa complex with a factor X mimetic reveals a novel allosteric mechanism. 著者: Josepha C Sedzro / Amanda L Photenhauer / Fabienne Birkle / Katarina Meze / Alex Mortenson / Cade Duckworth / Po-Chao Wen / Sarah Kearns / Michael A Cianfrocco / Emad Tajkhorshid / Melanie D ...著者: Josepha C Sedzro / Amanda L Photenhauer / Fabienne Birkle / Katarina Meze / Alex Mortenson / Cade Duckworth / Po-Chao Wen / Sarah Kearns / Michael A Cianfrocco / Emad Tajkhorshid / Melanie D Ohi / James H Morrissey / 要旨: Blood clotting is triggered in hemostasis and thrombosis when the membrane-bound tissue factor (TF)/factor VIIa (FVIIa) complex activates factor X (FX). There are no structures of TF/FVIIa on ...Blood clotting is triggered in hemostasis and thrombosis when the membrane-bound tissue factor (TF)/factor VIIa (FVIIa) complex activates factor X (FX). There are no structures of TF/FVIIa on membranes, with or without FX. Using cryo-EM to address this gap, we assembled TF/FVIIa complexes on nanoscale membrane bilayers (nanodiscs), bound to XK1 and an antibody fragment. XK1 is a FX mimetic whose protease domain is replaced by the first Kunitz-type (K1) domain of tissue factor pathway inhibitor, while 10H10 is a non-inhibitory, anti-TF antibody. We determined a cryo-EM structure of a TF/FVIIa/XK1/10H10/nanodisc complex with a resolution of 3.7 Å, allowing us to model all the protein backbones. TF/FVIIa extends perpendicularly from the membrane, interacting with a "handle shaped" XK1 at two locations: the K1 domain docks into FVIIa's active site, while the γ-carboxyglutamate-rich (GLA) domain binds to TF's substrate-binding exosite. The FX and FVIIa GLA domains also contact each other and the membrane surface. Except for a minor contact between the first epidermal growth factor (EGF)-like domain of XK1 and TF, the rest of the FX light chain does not interact with TF/FVIIa. The structure reveals a previously unrecognized, membrane-dependent allosteric activation mechanism between FVIIa and TF where a serine-rich loop in TF that partially obscures the TF exosite must undergo a shift to allow access of the FX GLA domain to its final binding location on the membrane-bound TF/FVIIa complex. This mechanism also provides a novel explanation for the otherwise puzzling phenomenon of TF encryption/decryption on cell surfaces.
全体 : Complex of factor VIIa, XK1 and the Fab fragment of antibody 10H1...
全体
名称: Complex of factor VIIa, XK1 and the Fab fragment of antibody 10H10, all bound to tissue factor embedded in a nanodisc membrane bilayer.
要素
複合体: Complex of factor VIIa, XK1 and the Fab fragment of antibody 10H10, all bound to tissue factor embedded in a nanodisc membrane bilayer.
複合体: Human 10H10 antibody Fab
タンパク質・ペプチド: Human 10H10 antibody Fab heavy chain
タンパク質・ペプチド: Human 10H10 antibody Fab light chain
複合体: XK1 chimeric protein
タンパク質・ペプチド: Human factor X (FX) light chain
タンパク質・ペプチド: Human TFPI Kunitz domain 1 (K1)
複合体: Human activated factor VIIa
タンパク質・ペプチド: Human factor VIIa (FVIIa) light chain
タンパク質・ペプチド: Human factor VIIa (FVIIa) protease domain
複合体: Human MBP-tagged tissue factor
タンパク質・ペプチド: Human tissue factor (TF)
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超分子 #1: Complex of factor VIIa, XK1 and the Fab fragment of antibody 10H1...
超分子
名称: Complex of factor VIIa, XK1 and the Fab fragment of antibody 10H10, all bound to tissue factor embedded in a nanodisc membrane bilayer. タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: all / 詳細: Map with nanodisc.
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超分子 #2: Human 10H10 antibody Fab
超分子
名称: Human 10H10 antibody Fab / タイプ: complex / ID: 2 / 親要素: 1 / 含まれる分子: #6-#7