3AT9
Crystal Structure of the Kir3.2 Cytoplasmic Domain (Na+-free crystal soaked in 10 mM barium chloride and 10 mM magnesium chloride)
Summary for 3AT9
| Entry DOI | 10.2210/pdb3at9/pdb |
| Related | 2e4f 3AT8 3ATA 3ATB 3ATD 3ATE 3ATF 3agw |
| Descriptor | Potassium inwardly-rectifying channel, subfamily J, member 6, MAGNESIUM ION (2 entities in total) |
| Functional Keywords | cytoplasmic assembly, beta-barrel, ion transport, g protein beta-gamma subunits, transport protein |
| Biological source | Mus musculus (mouse) More |
| Cellular location | Membrane ; Multi-pass membrane protein : Q0VB45 |
| Total number of polymer chains | 1 |
| Total formula weight | 23773.29 |
| Authors | Inanobe, A.,Kurachi, Y. (deposition date: 2010-12-28, release date: 2011-10-19, Last modification date: 2024-03-13) |
| Primary citation | Inanobe, A.,Nakagawa, A.,Kurachi, Y. Interactions of cations with the cytoplasmic pores of inward rectifier K(+) channels in the closed state J.Biol.Chem., 286:41801-41811, 2011 Cited by PubMed Abstract: 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. PubMed: 21982822DOI: 10.1074/jbc.M111.278531 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.3 Å) |
Structure validation
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