1F6G
POTASSIUM CHANNEL (KCSA) FULL-LENGTH FOLD
Summary for 1F6G
| Entry DOI | 10.2210/pdb1f6g/pdb |
| Related | 1bl8 |
| Descriptor | VOLTAGE-GATED POTASSIUM CHANNEL (1 entity in total) |
| Functional Keywords | potassium channel, integral membrane protein, cytoplasmic domains, proton transport, membrane protein |
| Biological source | Streptomyces lividans |
| Cellular location | Cell membrane; Multi-pass membrane protein: P0A334 |
| Total number of polymer chains | 4 |
| Total formula weight | 70141.50 |
| Authors | Cortes, D.M.,Perozo, E. (deposition date: 2000-06-21, release date: 2001-02-21, Last modification date: 2024-05-22) |
| Primary citation | Cortes, D.M.,Cuello, L.G.,Perozo, E. Molecular architecture of full-length KcsA: role of cytoplasmic domains in ion permeation and activation gating. J.Gen.Physiol., 117:165-180, 2001 Cited by PubMed Abstract: 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. PubMed: 11158168DOI: 10.1085/jgp.117.2.165 PDB entries with the same primary citation |
| Experimental method | SOLUTION NMR |
Structure validation
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