1a05
From Proteopedia
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| - | | | + | {{STRUCTURE_1a05| PDB=1a05 | SCENE= }} |
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'''CRYSTAL STRUCTURE OF THE COMPLEX OF 3-ISOPROPYLMALATE DEHYDROGENASE FROM THIOBACILLUS FERROOXIDANS WITH 3-ISOPROPYLMALATE''' | '''CRYSTAL STRUCTURE OF THE COMPLEX OF 3-ISOPROPYLMALATE DEHYDROGENASE FROM THIOBACILLUS FERROOXIDANS WITH 3-ISOPROPYLMALATE''' | ||
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[[Category: Tanaka, H.]] | [[Category: Tanaka, H.]] | ||
[[Category: Tanaka, N.]] | [[Category: Tanaka, N.]] | ||
| - | [[Category: | + | [[Category: Decarboxylating dehydrogenase]] |
| - | [[Category: | + | [[Category: Leucine biosynthesis]] |
| - | [[Category: | + | [[Category: Oxidoreductase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 09:36:32 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 06:36, 2 May 2008
CRYSTAL STRUCTURE OF THE COMPLEX OF 3-ISOPROPYLMALATE DEHYDROGENASE FROM THIOBACILLUS FERROOXIDANS WITH 3-ISOPROPYLMALATE
Overview
BACKGROUND: 3-Isopropylmalate dehydrogenase (IPMDH) and isocitrate dehydrogenase (ICDH) belong to a unique family of bifunctional decarboxylating dehydrogenases. Although the ICDH dimer catalyzes its reaction under a closed conformation, known structures of the IPMDH dimer (without substrate) adopt a fully open or a partially closed form. Considering the similarity in the catalytic mechanism, the IPMDH dimer must be in a fully closed conformation during the reaction. A large conformational change should therefore occur upon substrate binding. RESULTS: We have determined the crystal structure of IPMDH from Thiobacillus ferrooxidans (Tf) complexed with 3-isopropylmalate (IPM) at 2.0 A resolution by the molecular replacement method. The structure shows a fully closed conformation and the substrate-binding site is quite similar to that of ICDH except for a region around the gamma-isopropyl group. The gamma group is recognized by a unique hydrophobic pocket, which includes Glu88, Leu91 and Leu92 from subunit 1 and Val193' from subunit 2. CONCLUSIONS: A large movement of domain 1 is induced by substrate binding, which results in the formation of the hydrophobic pocket for the gamma-isopropyl moiety of IPM. A glutamic acid in domain 1, Glu88, participates in the formation of the hydrophobic pocket. The C beta and C gamma atoms of Glu88 interact with the gamma-isopropyl moiety of IPM and are central to the recognition of substrate. The acidic tip of Glu88 is likely to interact with the nicotinamide mononucleotide (NMN) ribose of NAD+ in the ternary complex. This structure clearly explains the substrate specificity of IPMDH.
About this Structure
1A05 is a Single protein structure of sequence from Acidithiobacillus ferrooxidans. Full crystallographic information is available from OCA.
Reference
Structure of 3-isopropylmalate dehydrogenase in complex with 3-isopropylmalate at 2.0 A resolution: the role of Glu88 in the unique substrate-recognition mechanism., Imada K, Inagaki K, Matsunami H, Kawaguchi H, Tanaka H, Tanaka N, Namba K, Structure. 1998 Aug 15;6(8):971-82. PMID:9739088 Page seeded by OCA on Fri May 2 09:36:32 2008
