Open AccessPreliminary X‐ray analysis of twinned crystals of sarcosine dimethylglycine methyltransferase from Halorhodospira halochoris
Author(s) -
Kallio Juha Pekka,
Jänis Janne,
Nyyssölä Antti,
Hakulinen Nina,
Rouvinen Juha
Publication year - 2009
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309109026232
Subject(s) - sarcosine , crystallography , chemistry , materials science , biochemistry , glycine , amino acid
Sarcosine dimethylglycine methyltransferase (EC 2.1.1.157) is an enzyme from the extremely halophilic anaerobic bacterium Halorhodospira halochoris . This enzyme catalyzes the twofold methylation of sarcosine to betaine, with S ‐adenosylmethionine (AdoMet) as the methyl‐group donor. This study presents the crystallization and preliminary X‐ray analysis of recombinant sarcosine dimethylglycine methyltransferase produced in Escherichia coli . Mass spectroscopy was used to determine the purity and homogeneity of the enzyme material. Two different crystal forms, which initially appeared to be hexagonal and tetragonal, were obtained. However, on analyzing the diffraction data it was discovered that both crystal forms were pseudo‐merohedrally twinned. The true crystal systems were monoclinic and orthorhombic. The monoclinic crystal diffracted to a maximum of 2.15 Å resolution and the orthorhombic crystal diffracted to 1.8 Å resolution.