1f6g
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POTASSIUM CHANNEL (KCSA) FULL-LENGTH FOLD
OverviewOverview
The molecular architecture of the NH(2) and COOH termini of the, prokaryotic potassium channel KcsA has been determined using site-directed, spin-labeling methods and paramagnetic resonance EPR spectroscopy., Cysteine mutants were generated (residues 5-24 and 121-160) and spin, labeled, and the X-band CW EPR spectra were obtained from, liposome-reconstituted channels at room temperature. Data on probe, mobility (DeltaHo(-1)), accessibility parameters (PiO(2) and PiNiEdda), and inter-subunit spin-spin interaction (Omega) were used as structural, constraints to build a three-dimensional folding model of these, cytoplasmic domains from a set of simulated annealing and restrained, molecular dynamics runs. 32 backbone structures were generated and, averaged using fourfold symmetry, and a final mean structure was obtained, from the eight lowest energy runs. Based on the present data, together, with information from the KcsA crystal structure, a model for the, three-dimensional fold of full-length KcsA was constructed. In this model, the NH(2) terminus of KcsA forms an alpha-helix anchored at the, membrane-water interface, while the COOH terminus forms a right-handed, four-helix bundle that extend some 40-50 A towards the cytoplasm., Functional analysis of COOH-terminal deletion constructs suggest that, while the COOH terminus does not play a substantial role in determining, ion permeation properties, it exerts a modulatory role in the pH-dependent, gating mechanism.
About this StructureAbout this Structure
1F6G is a Single protein structure of sequence from Streptomyces lividans. The following page contains interesting information on the relation of 1F6G with [Potassium Channels]. Full crystallographic information is available from OCA.
ReferenceReference
Molecular architecture of full-length KcsA: role of cytoplasmic domains in ion permeation and activation gating., Cortes DM, Cuello LG, Perozo E, J Gen Physiol. 2001 Feb;117(2):165-80. PMID:11158168
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