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==Crystal structure of Sulfolobus solfataricus ketol-acid reductoisomerase (Sso-KARI) in complex with Mg2+ at pH8.5== | |||
<StructureSection load='6jd2' size='340' side='right'caption='[[6jd2]], [[Resolution|resolution]] 2.53Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[6jd2]] is a 12 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6JD2 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6JD2 FirstGlance]. <br> | |||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=BME:BETA-MERCAPTOETHANOL'>BME</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></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='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=6jd2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6jd2 OCA], [http://pdbe.org/6jd2 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6jd2 RCSB], [http://www.ebi.ac.uk/pdbsum/6jd2 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6jd2 ProSAT]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
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. | |||
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> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
[[Category: | </div> | ||
<div class="pdbe-citations 6jd2" style="background-color:#fffaf0;"></div> | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Ketol-acid reductoisomerase]] | |||
[[Category: Large Structures]] | |||
[[Category: Chang, Y C]] | |||
[[Category: Chen, C Y]] | |||
[[Category: Hsieh, D L]] | |||
[[Category: Huang, C H]] | |||
[[Category: Ko, T P]] | |||
[[Category: Lin, B L]] | |||
[[Category: Lin, K F]] | |||
[[Category: Tsai, M D]] | |||
[[Category: Bi-specific]] | |||
[[Category: Dodecamer]] | |||
[[Category: Isomerase]] | |||
[[Category: Knotted protein]] | |||
[[Category: Magnesium-dependent]] | |||
[[Category: Reductoisomerase]] | |||
[[Category: Thermostable]] | |||
Revision as of 19:33, 14 August 2019
Crystal structure of Sulfolobus solfataricus ketol-acid reductoisomerase (Sso-KARI) in complex with Mg2+ at pH8.5Crystal structure of Sulfolobus solfataricus ketol-acid reductoisomerase (Sso-KARI) in complex with Mg2+ at pH8.5
Structural highlights
Publication Abstract from PubMedWhile 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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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