1v7l

Structure of 3-isopropylmalate isomerase small subunit from Pyrococcus horikoshii

spinqualitylabelsall models 1v7l, resolution 1.98Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1v7l is a 2 chain structure with sequence from Pyrococcus horikoshii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: PH1724 (Pyrococcus horikoshii) Activity: 3-isopropylmalate dehydratase, with EC number 4.2.1.33 Resources: FirstGlance, OCA, RCSB, PDBsum 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 Recent studies have implied that the isopropylmalate isomerase small subunit of the hyperthermophilic archaea Pyrococcus horikoshii (PhIPMI-s) functions as isopropylmalate isomerase in the leucine biosynthesis pathway, and as homoaconitase (HACN) in the lysine biosynthesis pathway via alpha-aminoadipic acid. PhIPMI is thus considered a key to understanding the fundamental metabolism of the earliest organisms. We describe for the first time the crystal structure of PhIPMI-s, which displays dual substrate specificity. The crystal structure unexpectedly shows that four molecules create an interlocked assembly with intermolecular disulfide linkages having a skewed 222 point-group symmetry. Although the overall fold of the PhIPMI-s monomer is related closely to domain 4 of the aconitase (ACN), one alpha-helix in the ACN structure is replaced by a short loop with relatively high temperature factor values. Because this region is essential for discriminating the structurally similar substrate based on interactions with its diversified gamma-moiety, the loop structure in the PhIPMI-s must be dependent on the presence of a substrate. The flexibility of the loop region might be a structural basis for recognizing both hydrophobic and hydrophilic gamma-moieties of two distinct substrates, isopropylmalate and homocitrate. Crystal structure of the Pyrococcus horikoshii isopropylmalate isomerase small subunit provides insight into the dual substrate specificity of the enzyme.,Yasutake Y, Yao M, Sakai N, Kirita T, Tanaka I J Mol Biol. 2004 Nov 19;344(2):325-33. PMID:15522288 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Isopropylmalate dehydrogenase

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