1U4F

Crystal Structure of Cytoplasmic Domains of IRK1 (Kir2.1) channel

Summary for 1U4F

• Entry DOI: 10.2210/pdb1u4f/pdb
• Related: 1N9P 1P7B 1U4E
• Descriptor: Inward rectifier potassium channel 2 (2 entities in total)
• Functional Keywords: cytoplasmic domain, kir2.1, irk1, inwardly rectifying k channel, rectification, allergen
• Biological source: Mus musculus (house mouse); More
• Cellular location: Membrane; Multi-pass membrane protein: P35561
• Total number of polymer chains: 4
• Total formula weight: 123362.32

Authors

Pegan, S.,Arrabit, C.,Zhou, W.,Kwiatkowski, W.,Slesinger, P.A.,Choe, S. (deposition date: 2004-07-24, release date: 2005-03-08, Last modification date: 2023-08-23)

Primary citation

Pegan, S.,Arrabit, C.,Zhou, W.,Kwiatkowski, W.,Collins, A.,Slesinger, P.A.,Choe, S.
Cytoplasmic domain structures of Kir2.1 and Kir3.1 show sites for modulating gating and rectification
Nat.Neurosci., 8:279-287, 2005

PubMed Abstract: 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.

PubMed: 15723059
DOI: 10.1038/nn1411

Experimental method

X-RAY DIFFRACTION (2.41 Å)