1bjn

STRUCTURE OF PHOSPHOSERINE AMINOTRANSFERASE FROM ESCHERICHIA COLI

spinqualitylabelsall models 1bjn, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1bjn is a 2 chain structure with sequence from "bacillus_coli"_migula_1895 "bacillus coli" migula 1895. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. NonStd Res: LLP Gene: SERC ("Bacillus coli" Migula 1895) Activity: Phosphoserine transaminase, with EC number 2.6.1.52 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [SERC_ECOLI] Catalyzes the reversible conversion of 3-phosphohydroxypyruvate to phosphoserine and of 3-hydroxy-2-oxo-4-phosphonooxybutanoate to phosphohydroxythreonine. Is involved in both pyridoxine and serine biosynthesis. 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 Phosphoserine aminotransferase (PSAT; EC 2.6.1.52), a member of subgroup IV of the aminotransferases, catalyses the conversion of 3-phosphohydroxypyruvate to l-phosphoserine. The crystal structure of PSAT from Escherichia coli has been solved in space group P212121 using MIRAS phases in combination with density modification and was refined to an R-factor of 17.5% (Rfree=20.1 %) at 2.3 A resolution. In addition, the structure of PSAT in complex with alpha-methyl-l-glutamate (AMG) has been refined to an R-factor of 18.5% (Rfree=25.1%) at 2.8 A resolution. Each subunit (361 residues) of the PSAT homodimer is composed of a large pyridoxal-5'-phosphate binding domain (residues 16-268), consisting of a seven-stranded mainly parallel beta-sheet, two additional beta-strands and seven alpha-helices, and a small C-terminal domain, which incorporates a five-stranded beta-sheet and two alpha-helices. A three-dimensional structural comparison to four other vitamin B6-dependent enzymes reveals that three alpha-helices of the large domain, as well as an N-terminal domain (subgroup II) or subdomain (subgroup I) are absent in PSAT. Its only 15 N-terminal residues form a single beta-strand, which participates in the beta-sheet of the C-terminal domain. The cofactor is bound through an aldimine linkage to Lys198 in the active site. In the PSAT-AMG complex Ser9 and Arg335 bind the AMG alpha-carboxylate group while His41, Arg42 and His328 are involved in binding the AMG side-chain. Arg77 binds the AMG side-chain indirectly through a solvent molecule and is expected to position itself during catalysis between the PLP phosphate group and the substrate side-chain. Comparison of the active sites of PSAT and aspartate aminotransferase suggests a similar catalytic mechanism, except for the transaldimination step, since in PSAT the Schiff base is protonated. Correlation of the PSAT crystal structure to a published profile sequence analysis of all subgroup IV members allows active site modelling of nifs and the proposal of a likely molecular reaction mechanism. Crystal structure of phosphoserine aminotransferase from Escherichia coli at 2.3 A resolution: comparison of the unligated enzyme and a complex with alpha-methyl-l-glutamate.,Hester G, Stark W, Moser M, Kallen J, Markovic-Housley Z, Jansonius JN J Mol Biol. 1999 Feb 26;286(3):829-50. PMID:10024454 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Phosphoserine aminotransferase

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