1jq1
From Proteopedia
(New page: 200px<br /><applet load="1jq1" size="450" color="white" frame="true" align="right" spinBox="true" caption="1jq1" /> '''POTASSIUM CHANNEL (KCSA) OPEN GATE MODEL'''<...) |
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| - | [[Image:1jq1.gif|left|200px]]<br /><applet load="1jq1" size=" | + | [[Image:1jq1.gif|left|200px]]<br /><applet load="1jq1" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1jq1" /> | caption="1jq1" /> | ||
'''POTASSIUM CHANNEL (KCSA) OPEN GATE MODEL'''<br /> | '''POTASSIUM CHANNEL (KCSA) OPEN GATE MODEL'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Ion channels catalyze the selective transfer of ions across the membrane | + | Ion channels catalyze the selective transfer of ions across the membrane in response to a variety of stimuli. These channels gate by controlling the access of ions to a centrally located water-filled pore. The crystal structure of the Streptomyces lividans potassium channel (KcsA) has allowed a molecular exploration of this mechanism. Electron paramagnetic resonance (EPR) studies have uncovered significant conformational changes at the intracellular end of the second transmembrane helix (TM2) upon gating. We have used site-directed spin labeling (SDSL) and EPR spectroscopy in an attempt to quantify the structural rearrangements of the KcsA TM2 bundle underlying the transition from the closed to the open state. Under conditions favoring the closed and open conformations, 10 intersubunit distances were obtained across TM2 segments from tandem dimer constructs. Analysis of these data points to a mechanism in which each TM2 helix tilts away from the permeation pathway, towards the membrane plane, and rotates about its helical axis, supporting a scissoring-type motion with a pivot point near residues 107-108. These movements are accompanied by a large increase in the diameter of the vestibule below the central water-filled cavity. |
==About this Structure== | ==About this Structure== | ||
| - | 1JQ1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptomyces_lividans Streptomyces lividans]. Full crystallographic information is available from [http:// | + | 1JQ1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Streptomyces_lividans Streptomyces lividans]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JQ1 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Streptomyces lividans]] | [[Category: Streptomyces lividans]] | ||
| - | [[Category: Liu, Y | + | [[Category: Liu, Y S.]] |
[[Category: Perozo, E.]] | [[Category: Perozo, E.]] | ||
[[Category: Sompornpisut, P.]] | [[Category: Sompornpisut, P.]] | ||
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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 13:25:23 2008'' |
Revision as of 11:25, 21 February 2008
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POTASSIUM CHANNEL (KCSA) OPEN GATE MODEL
Overview
Ion channels catalyze the selective transfer of ions across the membrane in response to a variety of stimuli. These channels gate by controlling the access of ions to a centrally located water-filled pore. The crystal structure of the Streptomyces lividans potassium channel (KcsA) has allowed a molecular exploration of this mechanism. Electron paramagnetic resonance (EPR) studies have uncovered significant conformational changes at the intracellular end of the second transmembrane helix (TM2) upon gating. We have used site-directed spin labeling (SDSL) and EPR spectroscopy in an attempt to quantify the structural rearrangements of the KcsA TM2 bundle underlying the transition from the closed to the open state. Under conditions favoring the closed and open conformations, 10 intersubunit distances were obtained across TM2 segments from tandem dimer constructs. Analysis of these data points to a mechanism in which each TM2 helix tilts away from the permeation pathway, towards the membrane plane, and rotates about its helical axis, supporting a scissoring-type motion with a pivot point near residues 107-108. These movements are accompanied by a large increase in the diameter of the vestibule below the central water-filled cavity.
About this Structure
1JQ1 is a Single protein structure of sequence from Streptomyces lividans. Full crystallographic information is available from OCA.
Reference
Structure of the KcsA channel intracellular gate in the open state., Liu YS, Sompornpisut P, Perozo E, Nat Struct Biol. 2001 Oct;8(10):883-7. PMID:11573095
Page seeded by OCA on Thu Feb 21 13:25:23 2008
