2fpx

Crystal Structure of the N-terminal Domain of E.coli HisB- Sulfate complex.

spinqualitylabelsall models 2fpx, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2fpx is a 2 chain structure with sequence from Escherichia coli O157:H7. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.8Å Ligands: MG, SO4, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function HIS7_ECO57 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 HisB from Escherichia coli is a bifunctional enzyme catalyzing the sixth and eighth steps of l-histidine biosynthesis. The N-terminal domain (HisB-N) possesses histidinol phosphate phosphatase activity, and its crystal structure shows a single domain with fold similarity to the haloacid dehalogenase (HAD) enzyme family. HisB-N forms dimers in the crystal and in solution. The structure shows the presence of a structural Zn(2+) ion stabilizing the conformation of an extended loop. Two metal binding sites were also identified in the active site. Their presence was further confirmed by isothermal titration calorimetry. HisB-N is active in the presence of Mg(2+), Mn(2+), Co(2+), or Zn(2+), but Ca(2+) has an inhibitory effect. We have determined structures of several intermediate states corresponding to snapshots along the reaction pathway, including that of the phosphoaspartate intermediate. A catalytic mechanism, different from that described for other HAD enzymes, is proposed requiring the presence of the second metal ion not found in the active sites of previously characterized HAD enzymes, to complete the second half-reaction. The proposed mechanism is reminiscent of two-Mg(2+) ion catalysis utilized by DNA and RNA polymerases and many nucleases. The structure also provides an explanation for the inhibitory effect of Ca(2+). Structural snapshots of Escherichia coli histidinol phosphate phosphatase along the reaction pathway.,Rangarajan ES, Proteau A, Wagner J, Hung MN, Matte A, Cygler M J Biol Chem. 2006 Dec 8;281(49):37930-41. Epub 2006 Sep 11. PMID:16966333 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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