View source for 7f6k


==Crystal structure of metal-citrate-binding protein (MctA) of ABC transporter endogenously bound to citrate==
<StructureSection load='7f6k' size='340' side='right'caption='[[7f6k]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7f6k]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermus_thermophilus_HB8 Thermus thermophilus HB8]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7F6K OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7F6K 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]] 2.1&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=CIT:CITRIC+ACID'>CIT</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=CO2:CARBON+DIOXIDE'>CO2</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=MES:2-(N-MORPHOLINO)-ETHANESULFONIC+ACID'>MES</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=7f6k FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7f6k OCA], [https://pdbe.org/7f6k PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7f6k RCSB], [https://www.ebi.ac.uk/pdbsum/7f6k PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7f6k ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q53VZ2_THET8 Q53VZ2_THET8] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
More than one third of proteins require metal ions to accomplish their functions, making them obligatory for the growth and survival of microorganisms in varying environmental niches. In prokaryotes, besides their involvement in various cellular and physiological processes, metal ions stimulate the uptake of citrate molecules. Citrate is a source of carbon and energy and is reported to be transported by secondary transporters. In Gram-positive bacteria, citrate molecules are transported in complex with divalent metal ions, whereas in Gram-negative bacteria they are translocated by Na(+)/citrate symporters. In this study, the presence of a novel divalent-metal-ion-complexed citrate-uptake system that belongs to the primary active ABC transporter superfamily is reported. For uptake, the metal-ion-complexed citrate molecules are sequestered by substrate-binding proteins (SBPs) and transferred to transmembrane domains for their transport. This study reports crystal structures of an Mg(2+)-citrate-binding protein (MctA) from the Gram-negative thermophilic bacterium Thermus thermophilus HB8 in both apo and holo forms in the resolution range 1.63-2.50 A. Despite binding various divalent metal ions, MctA possesses the coordination geometry to bind its physiological metal ion, Mg(2+). The results also suggest an extended subclassification of cluster D SBPs, which are known to bind and transport divalent-metal-ion-complexed citrate molecules. Comparative assessment of the open and closed conformations of the wild-type and mutant MctA proteins suggests a gating mechanism of ligand entry following an `asymmetric domain movement' of the N-terminal domain for substrate binding.

Structural and thermodynamic insights into a novel Mg(2+)-citrate-binding protein from the ABC transporter superfamily.,Mandal SK, Kanaujia SP Acta Crystallogr D Struct Biol. 2021 Dec 1;77(Pt 12):1516-1534. doi:, 10.1107/S2059798321010457. Epub 2021 Nov 11. PMID:34866608<ref>PMID:34866608</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7f6k" style="background-color:#fffaf0;"></div>

==See Also==
*[[ABC transporter 3D structures|ABC transporter 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Thermus thermophilus HB8]]
[[Category: Gogoi P]]
[[Category: Kanaujia SP]]
[[Category: Mandal SK]]