1jq2: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
==POTASSIUM CHANNEL (KCSA) OPEN GATE MODEL== | ==POTASSIUM CHANNEL (KCSA) OPEN GATE MODEL== | ||
<StructureSection load='1jq2' size='340' side='right' caption='[[1jq2]], [[NMR_Ensembles_of_Models | 50 NMR models]]' scene=''> | <StructureSection load='1jq2' size='340' side='right'caption='[[1jq2]], [[NMR_Ensembles_of_Models | 50 NMR models]]' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[1jq2]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/"actinomyces_lividans"_krasil'nikov_et_al._1965 "actinomyces lividans" krasil'nikov et al. 1965]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JQ2 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1JQ2 FirstGlance]. <br> | <table><tr><td colspan='2'>[[1jq2]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/"actinomyces_lividans"_krasil'nikov_et_al._1965 "actinomyces lividans" krasil'nikov et al. 1965]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JQ2 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1JQ2 FirstGlance]. <br> | ||
| Line 27: | Line 27: | ||
</StructureSection> | </StructureSection> | ||
[[Category: Actinomyces lividans krasil'nikov et al. 1965]] | [[Category: Actinomyces lividans krasil'nikov et al. 1965]] | ||
[[Category: Large Structures]] | |||
[[Category: Liu, Y S]] | [[Category: Liu, Y S]] | ||
[[Category: Perozo, E]] | [[Category: Perozo, E]] | ||
Revision as of 10:03, 10 July 2019
POTASSIUM CHANNEL (KCSA) OPEN GATE MODELPOTASSIUM CHANNEL (KCSA) OPEN GATE MODEL
Structural highlights
Function[KCSA_STRLI] Acts as a pH-gated potassium ion channel; changing the cytosolic pH from 7 to 4 opens the channel, although it is not clear if this is the physiological stimulus for channel opening. Monovalent cation preference is K(+) > Rb(+) > NH4(+) >> Na(+) > Li(+).[1] Publication Abstract from PubMedIon 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. 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[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
|
| ||||||||||||||||