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3ah3

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[[Image:3ah3.jpg|left|200px]]
 
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==Crystal structure of LR5-1, 3-isopropylmalate dehydrogenase created by directed evolution==
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The line below this paragraph, containing "STRUCTURE_3ah3", creates the "Structure Box" on the page.
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<StructureSection load='3ah3' size='340' side='right'caption='[[3ah3]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
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== Structural highlights ==
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or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
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<table><tr><td colspan='2'>[[3ah3]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermus_thermophilus_HB27 Thermus thermophilus HB27]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3AH3 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3AH3 FirstGlance]. <br>
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.4&#8491;</td></tr>
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<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>
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{{STRUCTURE_3ah3| PDB=3ah3 | SCENE= }}
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<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3ah3 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ah3 OCA], [https://pdbe.org/3ah3 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3ah3 RCSB], [https://www.ebi.ac.uk/pdbsum/3ah3 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3ah3 ProSAT]</span></td></tr>
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</table>
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== Function ==
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[https://www.uniprot.org/uniprot/HICDH_THET2 HICDH_THET2] Catalyzes the NAD(+)-dependent conversion of homoisocitrate to alpha-ketoadipate. In addition, has high activity with citrate, but is inactive with 3-isopropylmalate.<ref>PMID:12427751</ref> <ref>PMID:20735360</ref>
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<div style="background-color:#fffaf0;">
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== Publication Abstract from PubMed ==
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HICDH (homoisocitrate dehydrogenase), which is involved in lysine biosynthesis through alpha-aminoadipate, is a paralogue of IPMDH [3-IPM (3-isopropylmalate) dehydrogenase], which is involved in leucine biosynthesis. TtHICDH (Thermus thermophilus HICDH) can recognize isocitrate, as well as homoisocitrate, as the substrate, and also shows IPMDH activity, although at a considerably decreased rate. In the present study, the promiscuous TtHICDH was evolved into an enzyme showing distinct IPMDH activity by directed evolution using a DNA-shuffling technique. Through five repeats of DNA shuffling/screening, variants that allowed Escherichia coli C600 (leuB) to grow on a minimal medium in 2 days were obtained. One of the variants LR5-1, with eight amino acid replacements, was found to possess a 65-fold increased k(cat)/K(m) value for 3-IPM, compared with TtHICDH. Introduction of a single back-replacement H15Y change caused a further increase in the k(cat)/K(m) value and a partial recovery of the decreased thermotolerance of LR5-1. Site-directed mutagenesis revealed that most of the amino acid replacements found in LR5-1 effectively increased IPMDH activity; replacements around the substrate-binding site contributed to the improved recognition for 3-IPM, and other replacements at sites away from the substrate-binding site enhanced the turnover number for the IPMDH reaction. The crystal structure of LR5-1 was determined at 2.4 A resolution and revealed that helix alpha4 was displaced in a manner suitable for recognition of the hydrophobic gamma-moiety of 3-IPM. On the basis of the crystal structure, possible reasons for enhancement of the turnover number are discussed.
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===Crystal structure of LR5-1, 3-isopropylmalate dehydrogenase created by directed evolution===
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Enhancement of the latent 3-isopropylmalate dehydrogenase activity of promiscuous homoisocitrate dehydrogenase by directed evolution.,Suzuki Y, Asada K, Miyazaki J, Tomita T, Kuzuyama T, Nishiyama M Biochem J. 2010 Oct 11;431(3):401-10. PMID:20735360<ref>PMID:20735360</ref>
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From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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</div>
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<div class="pdbe-citations 3ah3" style="background-color:#fffaf0;"></div>
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==See Also==
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*[[Isocitrate dehydrogenase 3D structures|Isocitrate dehydrogenase 3D structures]]
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(as it appears on PubMed at http://www.pubmed.gov), where 20735360 is the PubMed ID number.
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== References ==
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<references/>
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{{ABSTRACT_PUBMED_20735360}}
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__TOC__
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</StructureSection>
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==About this Structure==
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[[Category: Large Structures]]
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[[3ah3]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3AH3 OCA].
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[[Category: Thermus thermophilus HB27]]
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[[Category: Kuzuyama T]]
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==Reference==
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[[Category: Nishiyama M]]
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<ref group="xtra">PMID:20735360</ref><references group="xtra"/>
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[[Category: Suzuki Y]]
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[[Category: Homoisocitrate dehydrogenase]]
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[[Category: Tomita T]]
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[[Category: Thermus thermophilus]]
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[[Category: Kuzuyama, T.]]
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[[Category: Nishiyama, M.]]
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[[Category: Suzuki, Y.]]
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[[Category: Tomita, T.]]
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Current revision

Crystal structure of LR5-1, 3-isopropylmalate dehydrogenase created by directed evolution

PDB ID 3ah3

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