3OUF

Structure of a K+ selective NaK mutant

Summary for 3OUF

• Entry DOI: 10.2210/pdb3ouf/pdb
• Descriptor: Potassium channel protein, (4S)-2-METHYL-2,4-PENTANEDIOL, POTASSIUM ION, ... (4 entities in total)
• Functional Keywords: ion channel, membrane, membrane protein
• Biological source: Bacillus cereus
• Total number of polymer chains: 2
• Total formula weight: 22486.10

Authors

Derebe, M.G.,Sauer, D.B.,Zeng, W.,Alam, A.,Shi, N.,Jiang, Y. (deposition date: 2010-09-14, release date: 2011-01-12, Last modification date: 2024-02-21)

Primary citation

Derebe, M.G.,Sauer, D.B.,Zeng, W.,Alam, A.,Shi, N.,Jiang, Y.
Tuning the ion selectivity of tetrameric cation channels by changing the number of ion binding sites.
Proc.Natl.Acad.Sci.USA, 108:598-602, 2011

PubMed Abstract: Selective ion conduction across ion channel pores is central to cellular physiology. To understand the underlying principles of ion selectivity in tetrameric cation channels, we engineered a set of cation channel pores based on the nonselective NaK channel and determined their structures to high resolution. These structures showcase an ensemble of selectivity filters with a various number of contiguous ion binding sites ranging from 2 to 4, with each individual site maintaining a geometry and ligand environment virtually identical to that of equivalent sites in K(+) channel selectivity filters. Combined with single channel electrophysiology, we show that only the channel with four ion binding sites is K(+) selective, whereas those with two or three are nonselective and permeate Na(+) and K(+) equally well. These observations strongly suggest that the number of contiguous ion binding sites in a single file is the key determinant of the channel's selectivity properties and the presence of four sites in K(+) channels is essential for highly selective and efficient permeation of K(+) ions.

PubMed: 21187421
DOI: 10.1073/pnas.1013636108

Experimental method

X-RAY DIFFRACTION (1.55 Å)