1f6g: Difference between revisions

Revision as of 15:57, 2 May 2008

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 Page seeded by OCA on Fri May 2 15:57:36 2008

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OCA

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 [[Image:1f6g.gif|left|200px]]
- {{Structure
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+The line below this paragraph, containing "STRUCTURE_1f6g", creates the "Structure Box" on the page.
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-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1f6g FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1f6g OCA], [http://www.ebi.ac.uk/pdbsum/1f6g PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1f6g RCSB]</span>
-}}
 '''POTASSIUM CHANNEL (KCSA) FULL-LENGTH FOLD'''
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 [[Category: Cortes, D M.]]
 [[Category: Perozo, E.]]
-[[Category: cytoplasmic domain]]
+[[Category: Cytoplasmic domain]]
-[[Category: integral membrane protein]]
+[[Category: Integral membrane protein]]
-[[Category: potassium channel]]
+[[Category: Potassium channel]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 15:57:36 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 20:16:52 2008''