6w0c

<table><tr><td colspan='2'>[[6w0c]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/"actinomyces_lividans"_krasil'nikov_et_al._1965 "actinomyces lividans" krasil'nikov et al. 1965] and [http://en.wikipedia.org/wiki/Buffalo_rat Buffalo rat]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6W0C OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=6W0C FirstGlance]. <br>

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

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">kcsA, skc1 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1916 "Actinomyces lividans" Krasil'nikov et al. 1965])</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=6w0c FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6w0c OCA], [http://pdbe.org/6w0c PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6w0c RCSB], [http://www.ebi.ac.uk/pdbsum/6w0c PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6w0c ProSAT]</span></td></tr>

== Function ==

[[http://www.uniprot.org/uniprot/KCSA_STRLI KCSA_STRLI]] Acts as a pH-gated potassium ion channel; changing the cytosolic pH from 7 to 4 opens the channel, although it is not clear if this is the physiological stimulus for channel opening. Monovalent cation preference is K(+) > Rb(+) > NH4(+) >> Na(+) > Li(+).<ref>PMID:7489706</ref>

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== Publication Abstract from PubMed ==

Barium (Ba(2+)) is a classic permeant blocker of potassium (K(+)) channels. The "external lock-in effect" in barium block experiments, whereby the binding of external K(+) impedes the forward translocation of the blocker, provides a powerful avenue to investigate the selectivity of the binding sites along the pore of potassium channels. Barium block experiments show that the external lock-in site is highly selective for K(+) over Na(+). Wild-type KcsA was crystallized in low K(+) conditions, and the crystals were soaked in solutions containing various concentrations of barium. Structural analysis reveals open and closed gate conformations of the KcsA channel. Anomalous diffraction experiments show that Ba(2+) primarily binds to the innermost site S4 of the selectivity filter of the open-gate conformation and also the site S2, but no binding is detected with the closed-gate conformation. Alchemical free-energy perturbation calculations indicate that the presence of a Ba(2+) ion in the selectivity filter boosts the specificity of K(+) binding relative to Na(+) in the external sites S0-S2.

 

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== References ==

[[Category: Actinomyces lividans krasil'nikov et al. 1965]]

[[Category: Buffalo rat]]

[[Category: Gong, L]]

[[Category: Li, J]]

[[Category: Rohaim, A]]

[[Category: Membrane protein]]