1f6g: Difference between revisions
New page: left|200px<br /> <applet load="1f6g" size="450" color="white" frame="true" align="right" spinBox="true" caption="1f6g" /> '''POTASSIUM CHANNEL (KCSA) FULL-LENGTH FOLD''... |
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[[Image:1f6g.gif|left|200px]]<br /> | [[Image:1f6g.gif|left|200px]]<br /><applet load="1f6g" size="350" color="white" frame="true" align="right" spinBox="true" | ||
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'''POTASSIUM CHANNEL (KCSA) FULL-LENGTH FOLD'''<br /> | '''POTASSIUM CHANNEL (KCSA) FULL-LENGTH FOLD'''<br /> | ||
==Overview== | ==Overview== | ||
The molecular architecture of the NH(2) and COOH termini of the | 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 Structure== | ==About this Structure== | ||
1F6G is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptomyces_lividans Streptomyces lividans]. The following page contains interesting information on the relation of 1F6G with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb38_1.html Potassium Channels]]. Full crystallographic information is available from [http:// | 1F6G is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptomyces_lividans Streptomyces lividans]. The following page contains interesting information on the relation of 1F6G with [[http://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb38_1.html Potassium Channels]]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1F6G OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Streptomyces lividans]] | [[Category: Streptomyces lividans]] | ||
[[Category: Cortes, D | [[Category: Cortes, D M.]] | ||
[[Category: Perozo, E.]] | [[Category: Perozo, E.]] | ||
[[Category: cytoplasmic domains]] | [[Category: cytoplasmic domains]] | ||
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[[Category: potassium channel]] | [[Category: potassium channel]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:35:21 2008'' | ||
Revision as of 13:35, 21 February 2008
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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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