Structural analysis of the KvAP voltage-dependent K+ channel reveals it requires a lipid membrane to maintain correct relative domain orientations and supports voltage sensing via a helix-turn-helix.
The study provides structural insights into the KvAP voltage-dependent K+ channel, highlighting the necessity of a lipid membrane for maintaining its native conformation.
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.
Lee et al. (Thu,) reported a other. KvAP voltage-dependent K+ channel structural analysis was evaluated. Structural analysis of the KvAP voltage-dependent K+ channel reveals it requires a lipid membrane to maintain correct relative domain orientations and supports voltage sensing via a helix-turn-helix.