3at8 | pdb_00003at8

Crystal Structure of the Kir3.2 Cytoplasmic Domain (Na+-free crystal soaked in 10 mM barium chloride)

spinqualitylabelsall models 3at8, resolution 3.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3at8 is a 1 chain structure with sequence from Lk3 transgenic mice. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: BA Related: 3agw, 2e4f, 3at9, 3ata, 3atb, 3atd, 3ate, 3atf Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Ion channels gate at membrane-embedded domains by changing their conformation along the ion conduction pathway. Inward rectifier K(+) (Kir) channels possess a unique extramembrane cytoplasmic domain that extends this pathway. However, the relevance and contribution of this domain to ion permeation remain unclear. By qualitative x-ray crystallographic analysis, we found that the pore in the cytoplasmic domain of Kir3.2 binds cations in a valency-dependent manner and does not allow the displacement of Mg(2+) by monovalent cations or spermine. Electrophysiological analyses revealed that the cytoplasmic pore of Kir3.2 selectively binds positively charged molecules and has a higher affinity for Mg(2+) when it has a low probability of being open. The selective blocking of chemical modification of the side chain of pore-facing residues by Mg(2+) indicates that the mode of binding of Mg(2+) is likely to be similar to that observed in the crystal structure. These results indicate that the Kir3.2 crystal structure has a closed conformation with a negative electrostatic field potential at the cytoplasmic pore, the potential of which may be controlled by conformational changes in the cytoplasmic domain to regulate ion diffusion along the pore. Interactions of cations with the cytoplasmic pores of inward rectifier K(+) channels in the closed state.,Inanobe A, Nakagawa A, Kurachi Y J Biol Chem. 2011 Dec 2;286(48):41801-11. Epub 2011 Oct 9. PMID:21982822 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Potassium Channel

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