Modulation of the conductance-voltage relationship of the BK Ca channel by mutations at the putative flexible interface between two RCK domains.

ABSTRACT: Calcium-dependent gating of the large-conductance Ca(2+)-activated K(+) (BK(Ca)) channel is conferred by the large cytosolic carboxyl terminus containing two domains of the regulator of K(+) conductance (RCK) and the high-affinity Ca(2+)-binding site (the Ca(2+)-bowl). In our previous study, we located the putative second RCK domain (RCK2) and demonstrated that it interacts directly with RCK1 via a hydrophobic "assembly interface". In this study, we tested the structural model of the other interface, the "flexible interface", by strategically positioning charge pairs across the putative interface. Several charge mutations on RCK2 affected the voltage-dependent activation of the channel. In particular, the Gly-to-Asp substitution at position 803 profoundly affected channel activation by sta

SUBMITTER: Kim HJ 

PROVIDER: S-EPMC2157237 | biostudies-literature | 2008 Jan

REPOSITORIES: biostudies-literature