Open AccessIn‐house SIRAS phasing of the polyunsaturated fatty‐acid isomerase from Propionibacterium acnes
Author(s) -
Liavonchanka Alena,
Hornung Ellen,
Feussner Ivo,
Rudolph Markus
Publication year - 2006
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309106001229
Subject(s) - monoclinic crystal system , conjugated linoleic acid , fatty acid , linoleic acid , isomerization , chemistry , cofactor , isomerase , crystal structure , polyunsaturated fatty acid , crystallization , crystal (programming language) , crystallography , stereochemistry , biochemistry , organic chemistry , enzyme , catalysis , computer science , programming language
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 I 2 1 3, with a unit‐cell parameter of 160.4 Å, and plate‐like crystals belong to the monoclinic space group C 2, with unit‐cell parameters a = 133.7, b = 60.8, c = 72.2 Å, β = 115.8°. Both crystal forms contain one molecule per asymmetric unit and diffract to a resolution of better than 2.0 Å. 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 .