3K6N

Crystal structure of the S225E mutant Kir3.1 cytoplasmic pore domain

Summary for 3K6N

• Entry DOI: 10.2210/pdb3k6n/pdb
• Related: 1N9P
• Descriptor: G protein-activated inward rectifier potassium channel 1, SODIUM ION (3 entities in total)
• Functional Keywords: beta barrel, cytoplasmic domain, g protein, inward rectifier, potassium channel, metal transport, ion transport, ionic channel, transmembrane
• Biological source: Mus musculus (mouse); More
• Cellular location: Membrane; Multi-pass membrane protein: P63250
• Total number of polymer chains: 1
• Total formula weight: 23730.87

Authors

Xu, Y.,Shin, H.G.,Szep, S.,Lu, Z. (deposition date: 2009-10-09, release date: 2009-11-17, Last modification date: 2023-09-06)

Primary citation

Xu, Y.,Shin, H.G.,Szep, S.,Lu, Z.
Physical determinants of strong voltage sensitivity of K(+) channel block.
Nat.Struct.Mol.Biol., 16:1252-1258, 2009

PubMed Abstract: Strong voltage sensitivity of inward-rectifier K(+) (Kir) channels has been hypothesized to arise primarily from an intracellular blocker displacing up to five K(+) ions from the wide, intracellular part of the ion conduction pore outwardly across the narrow ion-selectivity filter. The validity of this hypothesis depends on two assumptions: (i) that five ion sites are located intracellular to the filter and (ii) that the blocker can force essentially unidirectional K(+) movement in a pore region generally wider than the combined dimensions of the blocker plus a K(+) ion. Here we present a crystal structure of the cytoplasmic portion of a Kir channel with five ions bound and demonstrate that a constriction near the intracellular end of the pore, acting as a gasket, prevents K(+) ions from bypassing the blocker. This heretofore unrecognized 'gasket' ensures that the blocker can effectively displace K(+) ions across the selectivity filter to generate exceedingly strong voltage sensitivity.

PubMed: 19915587
DOI: 10.1038/nsmb.1717

Experimental method

X-RAY DIFFRACTION (2 Å)