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| ==Cryo-EM structure of Sulfolobus solfataricus ketol-acid reductoisomerase (Sso-KARI) with Mg2+ at pH7.5== | | ==Cryo-EM structure of Sulfolobus solfataricus ketol-acid reductoisomerase (Sso-KARI) with Mg2+ at pH7.5== |
| <StructureSection load='6jcv' size='340' side='right'caption='[[6jcv]], [[Resolution|resolution]] 2.92Å' scene=''> | | <SX load='6jcv' size='340' side='right' viewer='molstar' caption='[[6jcv]], [[Resolution|resolution]] 2.92Å' scene=''> |
| == Structural highlights == | | == Structural highlights == |
| <table><tr><td colspan='2'>[[6jcv]] is a 12 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6JCV OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6JCV FirstGlance]. <br> | | <table><tr><td colspan='2'>[[6jcv]] is a 12 chain structure with sequence from [https://en.wikipedia.org/wiki/Saccharolobus_solfataricus_P2 Saccharolobus solfataricus P2]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6JCV OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6JCV FirstGlance]. <br> |
| </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr> | | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 2.92Å</td></tr> |
| <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Ketol-acid_reductoisomerase Ketol-acid reductoisomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.86 1.1.1.86] </span></td></tr> | | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></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=6jcv FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6jcv OCA], [http://pdbe.org/6jcv PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6jcv RCSB], [http://www.ebi.ac.uk/pdbsum/6jcv PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6jcv ProSAT]</span></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=6jcv FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6jcv OCA], [https://pdbe.org/6jcv PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6jcv RCSB], [https://www.ebi.ac.uk/pdbsum/6jcv PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6jcv ProSAT]</span></td></tr> |
| </table> | | </table> |
| <div style="background-color:#fffaf0;">
| | == Function == |
| == Publication Abstract from PubMed == | | [https://www.uniprot.org/uniprot/ILVC2_SACS2 ILVC2_SACS2] |
| While cryo-EM is revolutionizing structural biology, its impact on enzymology is yet to be fully demonstrated. The ketol-acid reductoisomerase (KARI) catalyzes conversion of (2 S)-acetolactate or (2 S)-aceto-2-hydroxybutyrate to 2,3-dihydroxy-3-alkylbutyrate. We found that KARI from archaea Sulfolobus solfataricus (Sso-KARI) is unusual in being a dodecamer, bispecific to NADH and NADPH, and losing activity above pH 7.8. While crystals were obtainable only at pH 8.5, cryo-EM structures were solved at pH 7.5 and 8.5 for Sso-KARI:2Mg(2+). The results showed that the distances of the two catalytic Mg(2+) ions are lengthened in both structures at pH 8.5. We next solved cryo-EM structures of two Sso-KARI complexes, with NADH+inhibitor and NADPH+inhibitor at pH 7.5, which indicate that the bispecificity can be attributed to a unique asparagine at the cofactor binding loop. Unexpectedly, Sso-KARI also differs from other KARI enzymes in lacking "induced-fit", reflecting structural rigidity. Thus, cryo-EM is powerful for structural and mechanistic enzymology.
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| Use of Cryo-EM To Uncover Structural Bases of pH Effect and Cofactor Bispecificity of Ketol-Acid Reductoisomerase.,Chen CY, Chang YC, Lin BL, Lin KF, Huang CH, Hsieh DL, Ko TP, Tsai MD J Am Chem Soc. 2019 Apr 2. doi: 10.1021/jacs.9b01354. PMID:30921515<ref>PMID:30921515</ref>
| | ==See Also== |
| | | *[[Ketol-acid reductoisomerase 3D structures|Ketol-acid reductoisomerase 3D structures]] |
| 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 6jcv" style="background-color:#fffaf0;"></div>
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| == References == | |
| <references/>
| |
| __TOC__ | | __TOC__ |
| </StructureSection> | | </SX> |
| [[Category: Ketol-acid reductoisomerase]]
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| [[Category: Large Structures]] | | [[Category: Large Structures]] |
| [[Category: Chang, Y C]] | | [[Category: Saccharolobus solfataricus P2]] |
| [[Category: Chen, C Y]] | | [[Category: Chang YC]] |
| [[Category: Hsieh, D L]] | | [[Category: Chen CY]] |
| [[Category: Huang, C H]] | | [[Category: Hsieh DL]] |
| [[Category: Ko, T P]] | | [[Category: Huang CH]] |
| [[Category: Lin, B L]] | | [[Category: Ko TP]] |
| [[Category: Lin, K F]] | | [[Category: Lin BL]] |
| [[Category: Tsai, M D]] | | [[Category: Lin KF]] |
| [[Category: Bi-specific]]
| | [[Category: Tsai MD]] |
| [[Category: Dodecamer]]
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| [[Category: Isomerase]]
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| [[Category: Knot-structure]]
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| [[Category: Magnesium-dependent]]
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| [[Category: Reductoisomerase]]
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| [[Category: Thermostable]]
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