1iso

ISOCITRATE DEHYDROGENASE: STRUCTURE OF AN ENGINEERED NADP+--> NAD+ SPECIFICITY-REVERSAL MUTANT

spinqualitylabelsall models 1iso, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1iso is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.9Å Ligands: NAD, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function IDH_ECOLI Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The 7-fold mutation Cys201Met/Cys332Tyr/Lys344Asp/Tyr345Ile/Val35 1Ala/Tyr391Lys/Arg395Ser converts the cofactor specificity of Escherichia coli isocitrate dehydrogenase from a 7000-fold preference for NADP+ to a 200-fold preference for NAD+, with overall activity comparable to that of wild-type NAD+-dependent isocitrate dehydrogenases. The structure of the NAD+-dependent mutant has been determined and refined to a working R-factor of 0.186 at 1.9 A resolution. The structure shows that NADP+ affinity is destroyed by removing favorable interactions between the 2'-phosphate and Tyr345, Tyr391, and Arg395 and by adding a repulsive interaction with Asp344. NAD+ affinity is enhanced by adding hydrogen bonds between Asp344 and the free 2'-hydroxyl. The favorable Asp344-2'-OH interaction requires a change in the pucker of the ribose to C2' endo and a shift in the adenine ring. The ring shift is made possible by a series of changes in steric packing interactions. The linchpin for repacking in the adenosine binding site is residue 351. The side chain of this "second layer" residue dictates packing of the surrounding "first layer" residues which interact with the 2' moiety and, in turn, directly determine specificity. Determinants of cofactor specificity in isocitrate dehydrogenase: structure of an engineered NADP+ --> NAD+ specificity-reversal mutant.,Hurley JH, Chen R, Dean AM Biochemistry. 1996 May 7;35(18):5670-8. PMID:8639526 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Isocitrate dehydrogenase 3D structures

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