3den

Structure of E. coli DHDPS mutant Y107W

spinqualitylabelsall models 3den, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3den is a 2 chain structure with sequence from Ecoli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, K, PO4 NonStd Res: KGC Gene: dapA (ECOLI) Activity: 4-hydroxy-tetrahydrodipicolinate synthase, with EC number 4.3.3.7 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [DAPA_ECOLI] Catalyzes the condensation of (S)-aspartate-beta-semialdehyde [(S)-ASA] and pyruvate to 4-hydroxy-tetrahydrodipicolinate (HTPA). 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 Dihydrodipicolinate synthase (DHDPS) is a tetrameric enzyme that is the first enzyme unique to the ( S)-lysine biosynthetic pathway in plants and bacteria. Previous studies have looked at the important role of Tyr107, an amino acid residue located at the tight-dimer interface between two monomers, in participating in a catalytic triad of residues during catalysis. In this study, we examine the importance of this residue in determining the quaternary structure of the DHDPS enzyme. The Tyr107 residue was mutated to tryptophan, and structural, biophysical, and kinetic studies were carried out on the mutant enzyme. These revealed that while the solid-state structure of the mutant enzyme was largely unchanged, as judged by X-ray crystallography, it exists as a mixture of primarily monomer and tetramer in solution, as determined by analytical ultracentrifugation, size-exclusion chromatography, and mass spectrometry. The catalytic ability of the DHDPS enzyme was reduced by the mutation, which also allowed the adventitious binding of alpha-ketoglutarate to the active site. A reduction in the apparent melting temperature of the mutant enzyme was observed. Thus, the tetrameric quaternary structure of DHDPS is critical to controlling specificity, heat stability, and intrinsic activity. Mutating the tight-dimer interface of dihydrodipicolinate synthase disrupts the enzyme quaternary structure: toward a monomeric enzyme.,Pearce FG, Dobson RC, Weber A, Lane LA, McCammon MG, Squire MA, Perugini MA, Jameson GB, Robinson CV, Gerrard JA Biochemistry. 2008 Nov 18;47(46):12108-17. Epub 2008 Oct 21. PMID:18937497 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Dihydrodipicolinate synthase

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