1u4f
From Proteopedia
Crystal Structure of Cytoplasmic Domains of IRK1 (Kir2.1) channel
Overview
N- and C-terminal cytoplasmic domains of inwardly rectifying K (Kir) channels control the ion-permeation pathway through diverse interactions with small molecules and protein ligands in the cytoplasm. Two new crystal structures of the cytoplasmic domains of Kir2.1 (Kir2.1(L)) and the G protein-sensitive Kir3.1 (Kir3.1(S)) channels in the absence of PIP(2) show the cytoplasmic ion-permeation pathways occluded by four cytoplasmic loops that form a girdle around the central pore (G-loop). Significant flexibility of the pore-facing G-loop of Kir2.1(L) and Kir3.1(S) suggests a possible role as a diffusion barrier between cytoplasmic and transmembrane pores. Consistent with this, mutations of the G-loop disrupted gating or inward rectification. Structural comparison shows a di-aspartate cluster on the distal end of the cytoplasmic pore of Kir2.1(L) that is important for modulating inward rectification. Taken together, these results suggest the cytoplasmic domains of Kir channels undergo structural changes to modulate gating and inward rectification.
About this Structure
1U4F is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
Reference
Cytoplasmic domain structures of Kir2.1 and Kir3.1 show sites for modulating gating and rectification., Pegan S, Arrabit C, Zhou W, Kwiatkowski W, Collins A, Slesinger PA, Choe S, Nat Neurosci. 2005 Mar;8(3):279-87. Epub 2005 Feb 20. PMID:15723059 Page seeded by OCA on Sat May 3 10:45:05 2008
