Inward-rectifier potassium channel: Difference between revisions

The crystal structure<ref>{{cite journal | vauthors = Kuo A, Gulbis JM, Antcliff JF, Rahman T, Lowe ED, Zimmer J, Cuthbertson J, Ashcroft FM, Ezaki T, Doyle DA | display-authors = 6 | title = Crystal structure of the potassium channel KirBac1.1 in the closed state | journal = Science | volume = 300 | issue = 5627 | pages = 1922–6 | date = June 2003 | pmid = 12738871 | doi = 10.1126/science.1085028 | bibcode = 2003Sci...300.1922K | s2cid = 2703162 }}</ref> and function<ref name=":0">{{cite journal | vauthors = Enkvetchakul D, Bhattacharyya J, Jeliazkova I, Groesbeck DK, Cukras CA, Nichols CG | title = Functional characterization of a prokaryotic Kir channel | journal = The Journal of Biological Chemistry | volume = 279 | issue = 45 | pages = 47076–80 | date = November 2004 | pmid = 15448150 | doi = 10.1074/jbc.C400417200 | pmc = 8629170 | doi-access = free }}</ref> of bacterial members of the IRK-C family have been determined. KirBac1.1, from ''[[Burkholderia pseudomallei]]'', is 333 amino acyl residues (aas) long with two N-terminal TMSs flanking a P-loop (residues 1-150), and the C-terminal half of the protein is hydrophilic. It transports monovalent cations with the selectivity: K ≈ Rb ≈ Cs ≫ Li ≈ Na ≈ NMGM (protonated [[N-methyl-D-glucamine]]). Activity is inhibited by Ba²⁺, Ca²⁺, and low pH.<ref name=":0" />