1j1w
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Crystal Structure Of The Monomeric Isocitrate Dehydrogenase In Complex With NADP+
OverviewOverview
NADP+-dependent monomeric isocitrate dehydrogenase (IDH) from the, nitrogen-fixing bacterium Azotobacter vinelandii (AvIDH) is one of members, of the beta-decarboxylating dehydrogenase family and catalyzes the, dehydration and decarboxylation of isocitrate to yield 2-oxoglutrate and, CO2 in the Krebs cycle. We solved the crystal structure of the AvIDH in, complex with cofactor NADP+ (AvIDH-NADP+ complex). The final refined model, shows the closed form that has never been detected in any previously, solved structures of beta-decarboxylating dehydrogenases. The structure, also reveals all of the residues that interact with NADP+. The, structure-based sequence alignment reveals that these residues were not, conserved in any other dimeric NADP+-dependent IDHs. Therefore the NADP+, specificity of the monomeric and dimeric IDHs was independently acquired, through the evolutional process. The AvIDH was known to show an, exceptionally high turnover rate. The structure of the AvIDH-NADP+ complex, indicates that one loop, which is not present in the Escherichia coli, IDHs, reliably stabilizes the conformation of the nicotinamide, mononucleotide of the bound NADP+ by forming a few hydrogen bonds, and, such interactions are considered to be important for the monomeric enzyme, to initiate the hydride transfer reaction immediately. Finally, the, structure of the AvIDH is compared with that of other dimeric NADP-IDHs., Several structural features demonstrate that the monomeric IDHs are, structurally more related to the eukaryotic dimeric IDHs than to the, bacterial dimeric IDHs.
About this StructureAbout this Structure
1J1W is a Single protein structure of sequence from Azotobacter vinelandii with NAP as ligand. Active as Isocitrate dehydrogenase (NADP(+)), with EC number 1.1.1.42 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of the monomeric isocitrate dehydrogenase in the presence of NADP+: insight into the cofactor recognition, catalysis, and evolution., Yasutake Y, Watanabe S, Yao M, Takada Y, Fukunaga N, Tanaka I, J Biol Chem. 2003 Sep 19;278(38):36897-904. Epub 2003 Jul 10. PMID:12855708
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