title: In-house SIRAS phasing of the polyunsaturated fatty-acid isomerase from Propionibacterium acnes.
abstract: The polyenoic fatty-acid isomerase from Propionibacterium acnes (PAI) catalyzes the double-bond isomerization of linoleic acid to conjugated linoleic acid, which is a dairy- or meat-derived fatty acid in the human diet. PAI was overproduced in Escherichia coli and purified to homogeneity as a yellow-coloured protein. The nature of the bound cofactor was analyzed by absorption and fluorescence spectroscopy. Single crystals of PAI were obtained in two crystal forms. Cubic shaped crystals belong to space group I2(1)3, with a unit-cell parameter of 160.4 A, and plate-like crystals belong to the monoclinic space group C2, with unit-cell parameters a = 133.7, b = 60.8, c = 72.2 A, beta = 115.8 degrees. Both crystal forms contain one molecule per asymmetric unit and diffract to a resolution of better than 2.0 A. Initial phases were obtained by SIRAS from in-house data from a cubic crystal that was soaked with an unusually low KI concentration of 0.25 M.
authors.affiliation: Department of Plant Biochemistry, Georg-August-Universität, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany.
authors.forename: Alena
authors.initials: A
authors.lastname: Liavonchanka
authors.forename: Ellen
authors.initials: E
authors.lastname: Hornung
authors.forename: Ivo
authors.initials: I
authors.lastname: Feussner
authors.forename: Markus
authors.initials: M
authors.lastname: Rudolph
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D019748:Carbon-Carbon Double Bond Isomerases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D011425:Propionibacterium acnes / Q000201:enzymology*; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence
chemical_list: D001426:Bacterial Proteins; D019748:Carbon-Carbon Double Bond Isomerases; C105113:polyenoic fatty acid isomerase