4zzb
From Proteopedia
The GLIC pentameric Ligand-Gated Ion Channel Locally-closed form complexed to xenon
Structural highlights
Function[GLIC_GLOVI] Cationic channel with similar permeabilities for Na(+) and K(+), that is activated by an increase of the proton concentration on the extracellular side. Displays no permeability for chloride ions. Shows slow kinetics of activation, no desensitization and a single channel conductance of 8 pS. Might contribute to adaptation to external pH change.[1] Publication Abstract from PubMedGLIC receptor is a bacterial pentameric ligand-gated ion channel whose action is inhibited by xenon. Xenon has been used in clinical practice as a potent gaseous anaesthetic for decades, but the molecular mechanism of interactions with its integral membrane receptor targets remains poorly understood. Here we characterize by X-ray crystallography the xenon-binding sites within both the open and "locally-closed" (inactive) conformations of GLIC. Major binding sites of xenon, which differ between the two conformations, were identified in three distinct regions that all belong to the trans-membrane domain of GLIC: 1) in an intra-subunit cavity, 2) at the interface between adjacent subunits, and 3) in the pore. The pore site is unique to the locally-closed form where the binding of xenon effectively seals the channel. A putative mechanism of the inhibition of GLIC by xenon is proposed, which might be extended to other pentameric cationic ligand-gated ion channels. Structural Basis for Xenon Inhibition in a Cationic Pentameric Ligand-Gated Ion Channel.,Sauguet L, Fourati Z, Prange T, Delarue M, Colloc'h N PLoS One. 2016 Feb 24;11(2):e0149795. doi: 10.1371/journal.pone.0149795., eCollection 2016. PMID:26910105[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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