View source for 7kc7


==Biotin Carboxylase domain of Thermophilic 2-Oxoglutarate Carboxylase bound to ADP without Magnesium with disordered phosphate tail==
<StructureSection load='7kc7' size='340' side='right'caption='[[7kc7]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7kc7]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Hydrogenobacter_thermophilus Hydrogenobacter thermophilus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7KC7 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7KC7 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]] 2.2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ADP:ADENOSINE-5-DIPHOSPHATE'>ADP</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</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=7kc7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7kc7 OCA], [https://pdbe.org/7kc7 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7kc7 RCSB], [https://www.ebi.ac.uk/pdbsum/7kc7 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7kc7 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/2OCS_HYDTT 2OCS_HYDTT] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
2-Oxoglutarate carboxylase (OGC), a unique member of the biotin-dependent carboxylase family from the order Aquificales, captures dissolved CO2 via the reductive tricarboxylic acid (rTCA) cycle. Structure and function studies of OGC may facilitate adaptation of the rTCA cycle to increase the level of carbon fixation for biofuel production. Here we compare the biotin carboxylase (BC) domain of Hydrogenobacter thermophilus OGC with the well-studied mesophilic homologues to identify features that may contribute to thermal stability and activity. We report three OGC BC X-ray structures, each bound to bicarbonate, ADP, or ADP-Mg(2+), and propose that substrate binding at high temperatures is facilitated by interactions that stabilize the flexible subdomain B in a partially closed conformation. Kinetic measurements with varying ATP and biotin concentrations distinguish two temperature-dependent steps, consistent with biotin's rate-limiting role in organizing the active site. Transition state thermodynamic values derived from the Eyring equation indicate a larger positive DeltaH() and a less negative DeltaS() compared to those of a previously reported mesophilic homologue. These thermodynamic values are explained by partially rate limiting product release. Phylogenetic analysis of BC domains suggests that OGC diverged prior to Aquificales evolution. The phylogenetic tree identifies mis-annotations of the Aquificales BC sequences, including the Aquifex aeolicus pyruvate carboxylase structure. Notably, our structural data reveal that the OGC BC dimer comprises a "wet" dimerization interface that is dominated by hydrophilic interactions and structural water molecules common to all BC domains and likely facilitates the conformational changes associated with the catalytic cycle. Mutations in the dimerization domain demonstrate that dimerization contributes to thermal stability.

Structure, Function, and Thermal Adaptation of the Biotin Carboxylase Domain Dimer from Hydrogenobacter thermophilus 2-Oxoglutarate Carboxylase.,Buhrman G, Enriquez P, Dillard L, Baer H, Truong V, Grunden AM, Rose RB Biochemistry. 2021 Jan 19. doi: 10.1021/acs.biochem.0c00815. PMID:33464881<ref>PMID:33464881</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7kc7" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Hydrogenobacter thermophilus]]
[[Category: Large Structures]]
[[Category: Buhrman GK]]
[[Category: Enriquez P]]
[[Category: Rose RB]]
[[Category: Truong V]]