A novel magnesium‐dependent mechanism for the activation of transducin by fluoride

FEBS Letters

Bigay, Joelle¹  Chabre, Marc¹  Antonny, Bruno¹ 

[1] CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des Lucioles, Sophia Antipolis, F06560 Valbonne, France

关键词: Fluoride;    Magnesium;    Transducin;    G-protein;   

DOI  :  10.1016/0014-5793(90)81027-L

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Activation of transducin-GDP by NaF is mainly mediated by aluminofluoride or beryllofluoride complexes acting as GTP γ-phosphate analogs. In millimolar magnesium, NaF at concentrations above 3 mM is active even in the absence of aluminium or beryllium. This activation has a Hill coefficient of 3 with respect to F⁻, and its rate is linear with respect to Mg²⁺ concentrations above 2 mM. Upon fluoride dilution, inactivation rate is hundreds of times faster than for aluminofluoride-activated TαGDP. We propose that at high NaF concentrations, 3 hydrogen-bonded fluorides in the γ-phosphate site of TαGDP entrap a magnesium counterion and this induces the transconformation to the TαGTP form.

【 授权许可】

Unknown