3ous

<StructureSection load='3ous' size='340' side='right' caption='[[3ous]], [[Resolution|resolution]] 1.75&Aring;' scene=''>

<table><tr><td colspan='2'>[[3ous]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Metth Metth]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3OUS OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3OUS FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=K:POTASSIUM+ION'>K</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">mthK, MTH_1520 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=187420 METTH])</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3ous FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ous OCA], [http://pdbe.org/3ous PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3ous RCSB], [http://www.ebi.ac.uk/pdbsum/3ous PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3ous ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/MTHK_METTH MTHK_METTH]] Calcium-gated potassium channel.

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.

 

== References ==

[[Category: Metth]]

[[Category: Alam, A]]

[[Category: Derebe, M G]]

[[Category: Jiang, Y]]

[[Category: Sauer, D B]]

[[Category: Shi, N]]

[[Category: Zeng, W]]

[[Category: Membrane protein]]