title: Preliminary X-ray analysis of twinned crystals of sarcosine dimethylglycine methyltransferase from Halorhodospira halochoris.
abstract: 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 A resolution and the orthorhombic crystal diffracted to 1.8 A resolution.
authors: Department of Chemistry, University of Joensuu, 80101 Joensuu, Finland.
authors: Juha Pekka
authors: JP
authors: Kallio
authors: Janne
authors: J
authors: Jänis
authors: Antti
authors: A
authors: Nyyssölä
authors: Nina
authors: N
authors: Hakulinen
authors: Juha
authors: J
authors: Rouvinen
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D042001:Ectothiorhodospiraceae / Q000201:enzymology*; D005583:Fourier Analysis; D013058:Mass Spectrometry; D008780:Methyltransferases / Q000737:chemistry*; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D008780:Methyltransferases; C433447:sarcosine dimethylglycine methyltransferase, Halorhodospira halochloris