Coupling of proton source and sink via H+‐migration along the membrane surface as revealed by double patch‐clamp experiments

FEBS Letters

Antonenko, Yuri N²  Pohl, Peter¹ 

[1] Martin-Luther-Universität, Medizinische Fakultät, Institut für Medizinische Physik und Biophysik, 06097 Halle, Germany;A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia

关键词: Gramicidin;    Double patch-clamp;    Proton lateral conductance;    Planar bilayer lipid membrane;   

DOI  :  10.1016/S0014-5793(98)00590-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Long-range proton transfer along the surface of black lipid bilayers was observed between two integral membrane channels (gramicidins), one operating as a proton source, the other as a sink, by patch-clamp technique. In contrast, potassium ions were shown to equilibrate with the aqueous bulk phase before being consumed. Both channels opened and closed simultaneously only if the charge between them was carried by protons. In this case an anomalous high conductance between two patched membrane fragments was measured, each of them containing one single gramicidin channel. The coupled state disappeared when the distance between these two channels was increased above the critical value. The latter was shown to increase with the channel lifetime. Our results support the idea of the `localized' proton coupling, in which protons that have been pumped across membranes migrate along the membrane surface to reach another membrane protein that utilizes the established pH gradient.

【 授权许可】

Unknown