View source for 8b70


==KimA from B. subtilis with nucleotide second-messenger c-di-AMP bound==
<StructureSection load='8b70' size='340' side='right'caption='[[8b70]], [[Resolution|resolution]] 3.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8b70]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_subtilis Bacillus subtilis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8B70 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8B70 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=2BA:(2R,3R,3AS,5R,7AR,9R,10R,10AS,12R,14AR)-2,9-BIS(6-AMINO-9H-PURIN-9-YL)OCTAHYDRO-2H,7H-DIFURO[3,2-D 3,2-J][1,3,7,9,2,8]TETRAOXADIPHOSPHACYCLODODECINE-3,5,10,12-TETROL+5,12-DIOXIDE'>2BA</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=LMT:DODECYL-BETA-D-MALTOSIDE'>LMT</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=8b70 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8b70 OCA], [https://pdbe.org/8b70 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8b70 RCSB], [https://www.ebi.ac.uk/pdbsum/8b70 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8b70 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/KIMA_BACSU KIMA_BACSU] High-affinity potassium transporter (PubMed:28420751, PubMed:32005818). Functions as a K(+)/H(+) symporter (PubMed:32005818).<ref>PMID:28420751</ref> <ref>PMID:32005818</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Cyclic di-AMP is the only known essential second messenger in bacteria and archaea, regulating different proteins indispensable for numerous physiological processes. In particular, it controls various potassium and osmolyte transporters involved in osmoregulation. In Bacillus subtilis, the K(+)/H(+) symporter KimA of the KUP family is inactivated by c-di-AMP. KimA sustains survival at potassium limitation at low external pH by mediating potassium ion uptake. However, at elevated intracellular K(+) concentrations, further K(+) accumulation would be toxic. In this study, we reveal the molecular basis of how c-di-AMP binding inhibits KimA. We report cryo-EM structures of KimA with bound c-di-AMP in detergent solution and reconstituted in amphipols. By combining structural data with functional assays and molecular dynamics simulations we reveal how c-di-AMP modulates transport. We show that an intracellular loop in the transmembrane domain interacts with c-di-AMP bound to the adjacent cytosolic domain. This reduces the mobility of transmembrane helices at the cytosolic side of the K(+) binding site and therefore traps KimA in an inward-occluded conformation.

Cyclic di-AMP traps proton-coupled K(+) transporters of the KUP family in an inward-occluded conformation.,Fuss MF, Wieferig JP, Corey RA, Hellmich Y, Tascon I, Sousa JS, Stansfeld PJ, Vonck J, Hanelt I Nat Commun. 2023 Jun 21;14(1):3683. doi: 10.1038/s41467-023-38944-1. PMID:37344476<ref>PMID:37344476</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8b70" style="background-color:#fffaf0;"></div>

==See Also==
*[[Symporter 3D structures|Symporter 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Bacillus subtilis]]
[[Category: Large Structures]]
[[Category: Vonck J]]
[[Category: Wieferig JP]]