Structure of the KvAP voltage-dependent K+ channel and its dependence on the lipid membrane
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{sup +} channel KvAP, in complex with monoclonal Fv fragments (3.9 Angstroms) and without antibody fragments (8 Angstroms). 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.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States). National Synchrotron Light Source (NSLS)
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 913869
- Report Number(s):
- BNL-78437-2007-JA; PNASA6; TRN: US200804%%254
- Journal Information:
- Proc Natl Acad Sci USA, Vol. 102, Issue 43; ISSN 0027-8424
- Country of Publication:
- United States
- Language:
- English
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