3pg9

Thermotoga maritima DAH7P synthase in complex with inhibitor

spinqualitylabelsall models 3pg9, resolution 2.35Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3pg9 is a 8 chain structure with sequence from Thermotoga maritima. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.35Å Ligands: AZI, CL, NO3, TYR Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function AROF_THEMA Catalyzes the condensation of phosphoenolpyruvate (PEP) and D-erythrose-4-phosphate (E4P) giving rise to 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP). Publication Abstract from PubMed The first step of the shikimate pathway for aromatic amino acid biosynthesis is catalyzed by 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (DAH7PS). Thermotoga maritima DAH7PS (TmaDAH7PS) is tetrameric, with monomer units comprised of a core catalytic (beta/alpha)(8) barrel and an N-terminal domain. This enzyme is inhibited strongly by tyrosine and to a lesser extent by the presence of phenylalanine. A truncated mutant of TmaDAH7PS lacking the N-terminal domain was catalytically more active and completely insensitive to tyrosine and phenylalanine, consistent with a role for this domain in allosteric inhibition. The structure of this protein was determined to 2.0 A. In contrast to the wild-type enzyme, this enzyme is dimeric. Wild-type TmaDAH7PS was co-crystallized with tyrosine, and the structure of this complex was determined to a resolution of 2.35 A. Tyrosine was found to bind at the interface between two regulatory N-terminal domains, formed from diagonally located monomers of the tetramer, revealing a major reorganization of the regulatory domain with respect to the barrel relative to unliganded enzyme. This significant conformational rearrangement observed in the crystal structures was also clearly evident from small angle X-ray scattering measurements recorded in the presence and absence of tyrosine. The closed conformation adopted by the protein on tyrosine binding impedes substrate entry into the neighboring barrel, revealing an unusual tyrosine-controlled gating mechanism for allosteric control of this enzyme. Tyrosine latching of a regulatory gate affords allosteric control of aromatic amino acid biosynthesis.,Cross PJ, Dobson RC, Patchett ML, Parker EJ J Biol Chem. 2011 Mar 25;286(12):10216-24. Epub 2011 Jan 30. PMID:21282100 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also DAHP synthase 3D structures

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