Localization of the specific binding site for magnesium(II) ions in factor IX

FEBS Letters

Yamashita, Toshiko¹  Sekiya, Fujio¹  Morita, Takashi¹  Yoshida, Misa¹ 

[1] Department of Biochemistry, Meiji College of Pharmacy, Yato-cho, Tanashi, Tokyo 188, Japan

关键词: Factor IX;    Mg2+ ion;    Ca2+ ion;    Gla domain;   

DOI  :  10.1016/0014-5793(96)00813-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We demonstrated recently that coagulation factor IX has a specific binding site(s) for Mg²⁺ ions, independent of the Ca²⁺-binding sites, and that binding of Mg²⁺ ions is very important for expression of the functional conformation of this protein. We report here the localization of this Mg²⁺-specific binding site. We prepared three Gla-containing fragments of bovine factor IX, namely GlaEGF_NC (residues 1–144+286–296), GlaEGF_N (1–83) and the Gla domain peptide (1–46). Fragments GlaEGF_NC and GlaEGF_N retained the ability to undergo a conformational change upon binding of Mg²⁺ ions in the presence of excess Ca²⁺ ions. This change could be detected by a conformation-specific antibody. Furthermore, the Gla domain peptide was capable of binding Mg²⁺ ions, as determined by the metal ion-induced quenching of the intrinsic fluorescence. It appears that the Mg²⁺-specific binding site of factor IX is located in the N-terminal Gla domain.

【 授权许可】

Unknown