Fast and slow kinetics of porin channels from Escherichia coli reconstituted into giant liposomes and studied by patch‐clamp

FEBS Letters

Houssin, Christine²  Coulombe, Alain¹  Ghazi, Alexandre²  Berrier, Catherine² 

[1] Laboratoire de Physiologie Cellulaire, URA CNRS 1121, Université Paris-Sud, 91405 Orsay Cedex, France;Laboratoire des Biomembranes, URA CNRS 1116, Université Paris-Sud, 91405 Orsay Cedex, France

关键词: Porin;    Ion channel;    Liposome;    Patch-clamp;    Escherichia coli;   

DOI  :  10.1016/0014-5793(92)81011-A

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

E. coli porins (OmpF and OmpC) were purified and reconstituted into liposomes which were enlarged to giant proteoliposomes by dehydration—rehydration and studied by patch-clamp. The porins could be closed by voltage pulses under −100mV. The kinetics of closure was slow, with closure events of about 200 pS in 0.1 M KCl. Rapid fluctuations (in the millisecond range) of about one third (60–70 pS) of the large closure steps were also observed. The data are interpreted as follows: an increase in membrane potential favours the cooperative transition of multimers towards an inactivated state, while monomers which have not been inactivated can flicker rapidly between an open and a short-lived closed state.

【 授权许可】

Unknown