title: Purification, crystallization and preliminary X-ray diffraction analysis of the seryl-tRNA synthetase from Candida albicans.
abstract: The seryl-tRNA synthetase (SerRS) from Candida albicans exists naturally as two isoforms resulting from ambiguity in the natural genetic code. Both enzymes were crystallized by the sitting-drop vapour-diffusion method using 3.2-3.4 M ammonium sulfate as precipitant. The crystals belonged to the hexagonal space group P6(1)22 and contained one monomer per asymmetric unit, despite the synthetase existing as a homodimer (with a molecular weight of ∼116 kDa) in solution. Diffraction data were collected to 2.0 Å resolution at a synchrotron source and the crystal structures of unliganded SerRS and of its complexes with ATP and with a seryl-adenylate analogue were solved by molecular replacement. The structure of C. albicans SerRS represents the first reported structure of a eukaryotic cytoplasmic SerRS.
authors.affiliation: IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal.
authors.forename: Rita
authors.initials: R
authors.lastname: Rocha
authors.forename: Pedro José
authors.initials: PJ
authors.lastname: Barbosa Pereira
authors.forename: Manuel A S
authors.initials: MA
authors.lastname: Santos
authors.forename: Sandra
authors.initials: S
authors.lastname: Macedo-Ribeiro
mesh_terms: D002176:Candida albicans / Q000201:enzymology*; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D012714:Serine-tRNA Ligase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*
chemical_list: D005656:Fungal Proteins; D007527:Isoenzymes; D011994:Recombinant Proteins; D012714:Serine-tRNA Ligase