Referenced in: none

Automatically associated channels: Kv1.2

Title: Structure of the KvAP voltage-dependent K+ channel and its dependence on the lipid membrane.

Authors: Seok-Yong Lee, Alice Lee, Jiayun Chen, Roderick MacKinnon

Journal, date & volume: Proc. Natl. Acad. Sci. U.S.A., 2005 Oct 25 , 102, 15441-6

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/16223877

Abstract
Voltage-dependent ion channels gate open in response to changes in cell membrane voltage. This form of gating permits the propagation of action potentials. We present two structures of the voltage-dependent K(+) channel KvAP, in complex with monoclonal Fv fragments (3.9 A) and without antibody fragments (8 A). We also studied KvAP with disulfide cross-bridges in lipid membranes. Analyzing these data in the context of the crystal structure of Kv1.2 and EPR data on KvAP we reach the following conclusions: (i) KvAP is similar in structure to Kv1.2 with a very modest difference in the orientation of its voltage sensor; (ii) mAb fragments are not the source of non-native conformations of KvAP in crystal structures; (iii) because KvAP contains separate loosely adherent domains, a lipid membrane is required to maintain their correct relative orientations, and (iv) the model of KvAP is consistent with the proposal of voltage sensing through the movement of an arginine-containing helix-turn-helix element at the protein-lipid interface.