3ggg

The crystal structure of A. aeolicus prephenate dehydrogenase in complex with tyrosine and NAD+

spinqualitylabelsall models 3ggg, resolution 2.21Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3ggg is a 4 chain structure with sequence from Aquifex aeolicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.21Å Ligands: NAD, TYR Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function O67636_AQUAE 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 TyrA proteins belong to a family of dehydrogenases that are dedicated to l-tyrosine biosynthesis. The three TyrA subclasses are distinguished by their substrate specificities, namely the prephenate dehydrogenases, the arogenate dehydrogenases, and the cyclohexadienyl dehydrogenases, which utilize prephenate, l-arogenate, or both substrates, respectively. The molecular mechanism responsible for TyrA substrate selectivity and regulation is unknown. To further our understanding of TyrA-catalyzed reactions, we have determined the crystal structures of Aquifex aeolicus prephenate dehydrogenase bound with NAD(+) plus either 4-hydroxyphenylpyuvate, 4-hydroxyphenylpropionate, or l-tyrosine and have used these structures as guides to target active site residues for site-directed mutagenesis. From a combination of mutational and structural analyses, we have demonstrated that His-147 and Arg-250 are key catalytic and binding groups, respectively, and Ser-126 participates in both catalysis and substrate binding through the ligand 4-hydroxyl group. The crystal structure revealed that tyrosine, a known inhibitor, binds directly to the active site of the enzyme and not to an allosteric site. The most interesting finding though, is that mutating His-217 relieved the inhibitory effect of tyrosine on A. aeolicus prephenate dehydrogenase. The identification of a tyrosine-insensitive mutant provides a novel avenue for designing an unregulated enzyme for application in metabolic engineering. The crystal structure of Aquifex aeolicus prephenate dehydrogenase reveals the mode of tyrosine inhibition.,Sun W, Shahinas D, Bonvin J, Hou W, Kimber MS, Turnbull J, Christendat D J Biol Chem. 2009 May 8;284(19):13223-32. Epub 2009 Mar 10. PMID:19279014 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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