EPR spectroscopy of 5‐DOXYL‐stearic acid bound to the mitochondrial uncoupling protein reveals its competitive displacement by alkylsulfonates in the channel and allosteric displacement by ATP

FEBS Letters

Trommer, Wolfgang E.²  Bauer, Michael²  Ježek, Petr¹ 

[1] Institute of Physiology, Department of Membrane Transport Biophysics, Academy of Sciences of the Czech Republic Vídeňska 1083, CZ 14220 Prague, Czech Republic;Fachbereich Chemie, Universität Kaiserslautern, Erwin-Schrödinger Strasse, D-67663 Kaiserslautern, Germany

关键词: Uncoupling protein;    Anion channel;    Alkylsulfonate;    Fatty acid binding site;    5-DOXYL-stearic acid;    BAT;    brown adipose tissue;    NEM;    N-ethylmaleimide;    5-SASL;    5-DOXYL-stearic acid;    where DOXYL is 4;    4-dimethyl-3-oxazolinyloxy-residue;    N 6-SL-ATP;    N 6-(2;    2;    6;    6-tetramethyl-piperidin4-yl-1-oxyl)-ATP;    TEA;    tetraethylammonium;    TES;    N-Tris(hydroxymethyl)methyl)-2-aminoethane-sulfonic acid;    UcP;    uncoupling protein;   

DOI  :  10.1016/0014-5793(95)00201-J

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Competition of fatty acids (FA) and alkylsulfonates with 5-DOXYL-stearic acid (5-SASL) binding to isolated mitochondrial uncoupling protein (UcP) is demonstrated using EPR spectroscopy. A distinct peak of the bound 5-SASL (h_+1I) decreased with increasing concentration of competitors. Since alkylsulfonates are UcP substrates, it suggests that the FA binding site is located in the anion channel. Moreover, with increasing ATP the h_+1I peak decreased and was smoothed with the ‘micellar’ peak into a single wider peak. A pH of 8.5 reversed this effect. It could reflect an allosteric release of 5-SASL from the ATP binding site which mimics the ATP gating mechanism.

【 授权许可】

Unknown