View source for 6lsc


==Structure of the E202Y mutant of the Cl-/H+ antiporter CLC-ec1 from E.coli: a re-refined model of the 4FTP model==
<StructureSection load='6lsc' size='340' side='right'caption='[[6lsc]], [[Resolution|resolution]] 3.21&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6lsc]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=4ftp 4ftp]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6LSC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6LSC FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.21&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=6lsc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6lsc OCA], [https://pdbe.org/6lsc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6lsc RCSB], [https://www.ebi.ac.uk/pdbsum/6lsc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6lsc ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CLCA_ECOLI CLCA_ECOLI] Proton-coupled chloride transporter. Functions as antiport system and exchanges two chloride ions for 1 proton. Probably acts as an electrical shunt for an outwardly-directed proton pump that is linked to amino acid decarboxylation, as part of the extreme acid resistance (XAR) response.<ref>PMID:12384697</ref> <ref>PMID:14985752</ref> <ref>PMID:16341087</ref> <ref>PMID:16905147</ref> <ref>PMID:18678918</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Chloride-transporting membrane proteins of the CLC family appear in two distinct mechanistic flavors: H(+)-gated Cl(-) channels and Cl(-)/H(+) antiporters. Transmembrane H(+) movement is an essential feature of both types of CLC. X-ray crystal structures of CLC antiporters show the Cl(-) ion pathway through these proteins, but the H(+) pathway is known only inferentially by two conserved glutamate residues that act as way-stations for H(+) in its path through the protein. The extracellular-facing H(+) transfer glutamate becomes directly exposed to aqueous solution during the transport cycle, but the intracellular glutamate E203, Glu(in), is buried within the protein. Two regions, denoted "polar" and "interfacial," at the intracellular surface of the bacterial antiporter CLC-ec1 are examined here as possible pathways by which intracellular aqueous protons gain access to Glu(in). Mutations at multiple residues of the polar region have little effect on antiport rates. In contrast, mutation of E202, a conserved glutamate at the protein-water boundary of the interfacial region, leads to severe slowing of the Cl(-)/H(+) antiport rate. An X-ray crystal structure of E202Y, the most strongly inhibited of these substitutions, shows an aqueous portal leading to Glu(in) physically blocked by cross-subunit interactions; moreover, this mutation has only minimal effect on a monomeric CLC variant, which necessarily lacks such interactions. The several lines of experiments presented argue that E202 acts as a water-organizer that creates a proton conduit connecting intracellular solvent with Glu(in).

Intracellular proton access in a cl(-)/h(+) antiporter.,Lim HH, Shane T, Miller C PLoS Biol. 2012 Dec;10(12):e1001441. doi: 10.1371/journal.pbio.1001441. Epub 2012, Dec 11. PMID:23239938<ref>PMID:23239938</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6lsc" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ion channels 3D structures|Ion channels 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli K-12]]
[[Category: Large Structures]]
[[Category: Lim HH]]
[[Category: Miller C]]
[[Category: Shane T]]