1jq1
From Proteopedia
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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 Tue Nov 20 18:28:05 2007
