Characterization of the interaction between the light chain of factor VIIa and tissue factor

FEBS Letters

Persson, Egon¹ 

[1] Vessel Wall Biology, Health Care Discovery, Novo Nordisk A/S, Niels Steensens Vej 1, DK-2820 Gentofte, Denmark

关键词: Ca2+ binding;    Factor VIIa;    Gla domain;    Light chain;    Surface plasmon resonance;    Tissue factor;    fVIIa;    factor VIIa;    des(1–38)-fVIIa;    fVIIa lacking the N-terminal 38 amino acid residues;    fVII-GlaEGFNC;    residues 1–144 plus 248–266 of fVIIa;    Gla;    γ-carboxyglutamic acid;    EGF;    epidermal growth factor;    TF;    tissue factor;    sTF;    the soluble;    extracellular part of TF (residues 1–219);    Kd;    equilibrium dissociation constant;   

DOI  :  10.1016/S0014-5793(97)00941-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Factor VIIa (fVIIa) consists of a heavy chain (serine protease domain) and a light chain (γ-carboxyglutamic acid (Gla)-rich and epidermal growth factor (EGF)-like domains). The light chain, primarily the first EGF-like domain, appears to provide most of the binding energy in the interaction with tissue factor (TF). The Ca²⁺-binding sites in the protease domain and in the first EGF-like domain influence activity and interaction with TF, but the contribution from the Ca²⁺-binding sites in the Gla domain has not been established. We have compared the soluble TF (sTF)-binding properties of intact fVIIa to those of a fragment comprising almost the entire light chain and a small disulphide-linked peptide from the protease domain. Half-maximal binding of fVIIa and the light chain to sTF occurred around 0.3 and 1 mM Ca²⁺, respectively. The Ca²⁺ dependence of light-chain binding indicates an influence of Ca²⁺ binding to the Gla domain on the interaction between fVIIa and sTF. Comparison of the sTF-binding properties of fVIIa and a truncated variant lacking the Gla domain suggests that this domain interferes with sTF association at suboptimal Ca²⁺ concentrations. The light chain of fVIIa associated 5-fold slower with sTF than did fVIIa at saturating Ca²⁺ concentrations, whereas the dissociation of its complex with sTF was at least 100-fold faster than that of fVIIa:sTF. This gave a dissociation constant of 1–2 μM for the interaction between the light chain and sTF compared to about 3 nM for the fVIIa:sTF interaction.

【 授权许可】

Unknown