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| | ==Structure of native YfkE== | | ==Structure of native YfkE== |
| - | <StructureSection load='4kjs' size='340' side='right' caption='[[4kjs]], [[Resolution|resolution]] 3.05Å' scene=''> | + | <StructureSection load='4kjs' size='340' side='right'caption='[[4kjs]], [[Resolution|resolution]] 3.05Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[4kjs]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Bacsu Bacsu]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4KJS OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4KJS FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[4kjs]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_subtilis_subsp._subtilis_str._168 Bacillus subtilis subsp. subtilis str. 168]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4KJS OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4KJS FirstGlance]. <br> |
| - | </td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4kjr|4kjr]]</td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.05Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">yfkE, BSU07920 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=224308 BACSU])</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=4kjs FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4kjs OCA], [https://pdbe.org/4kjs PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4kjs RCSB], [https://www.ebi.ac.uk/pdbsum/4kjs PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4kjs ProSAT]</span></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=4kjs FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4kjs OCA], [http://pdbe.org/4kjs PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4kjs RCSB], [http://www.ebi.ac.uk/pdbsum/4kjs PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4kjs ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| - | <div style="background-color:#fffaf0;">
| + | == Function == |
| - | == Publication Abstract from PubMed == | + | [https://www.uniprot.org/uniprot/CHAA_BACSU CHAA_BACSU] Ca(+)/H(+) antiporter that extrudes calcium in exchange for external protons. Does not transport sodium or potassium.<ref>PMID:19543710</ref> |
| - | Ca(2+) efflux by Ca(2+) cation antiporter (CaCA) proteins is important for maintenance of Ca(2+) homeostasis across the cell membrane. Recently, the monomeric structure of the prokaryotic Na(+)/Ca(2+) exchanger (NCX) antiporter NCX_Mj protein from Methanococcus jannaschii shows an outward-facing conformation suggesting a hypothesis of alternating substrate access for Ca(2+) efflux. To demonstrate conformational changes essential for the CaCA mechanism, we present the crystal structure of the Ca(2+)/H(+) antiporter protein YfkE from Bacillus subtilis at 3.1-A resolution. YfkE forms a homotrimer, confirmed by disulfide crosslinking. The protonated state of YfkE exhibits an inward-facing conformation with a large hydrophilic cavity opening to the cytoplasm in each protomer and ending in the middle of the membrane at the Ca(2+)-binding site. A hydrophobic "seal" closes its periplasmic exit. Four conserved alpha-repeat helices assemble in an X-like conformation to form a Ca(2+)/H(+) exchange pathway. In the Ca(2+)-binding site, two essential glutamate residues exhibit different conformations compared with their counterparts in NCX_Mj, whereas several amino acid substitutions occlude the Na(+)-binding sites. The structural differences between the inward-facing YfkE and the outward-facing NCX_Mj suggest that the conformational transition is triggered by the rotation of the kink angles of transmembrane helices 2 and 7 and is mediated by large conformational changes in their adjacent transmembrane helices 1 and 6. Our structural and mutational analyses not only establish structural bases for mechanisms of Ca(2+)/H(+) exchange and its pH regulation but also shed light on the evolutionary adaptation to different energy modes in the CaCA protein family.
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| - | Crystal structure of Ca2+/H+ antiporter protein YfkE reveals the mechanisms of Ca2+ efflux and its pH regulation.,Wu M, Tong S, Waltersperger S, Diederichs K, Wang M, Zheng L Proc Natl Acad Sci U S A. 2013 Jul 9;110(28):11367-72. doi:, 10.1073/pnas.1302515110. Epub 2013 Jun 24. PMID:23798403<ref>PMID:23798403</ref>
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| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
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| - | </div>
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| - | <div class="pdbe-citations 4kjs" style="background-color:#fffaf0;"></div>
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| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Bacsu]] | + | [[Category: Bacillus subtilis subsp. subtilis str. 168]] |
| - | [[Category: Tong, S]] | + | [[Category: Large Structures]] |
| - | [[Category: Wu, M]] | + | [[Category: Tong S]] |
| - | [[Category: Zheng, L]] | + | [[Category: Wu M]] |
| - | [[Category: Ca/h+ antiporter]] | + | [[Category: Zheng L]] |
| - | [[Category: Caca]]
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| - | [[Category: Cax]]
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| - | [[Category: Transport protein]]
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| - | [[Category: Yfke]]
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