Permeation and gating of an inwardly rectifying potassium channel. Evidence for a variable energy well.

ABSTRACT: Permeation, gating, and their interrelationship in an inwardly rectifying potassium (K+) channel, ROMK2, were studied using heterologous expression in Xenopus oocytes. Patch-clamp recordings of single channels were obtained in the cell-attached mode. The gating kinetics of ROMK2 were well described by a model having one open and two closed states. One closed state was short lived (approximately 1 ms) and the other was longer lived (approximately 40 ms) and less frequent (approximately 1%). The long closed state was abolished by EDTA, suggesting that it was due to block by divalent cations. These closures exhibit a biphasic voltage dependence, implying that the divalent blockers can permeate the channel. The short closures had a similar biphasic voltage dependence, suggesting that they coul

SUBMITTER: Choe H 

PROVIDER: S-EPMC2229425 | biostudies-literature | 1998 Oct

REPOSITORIES: biostudies-literature