Preliminary X-ray analysis of twinned crystals of sarcosine dimethylglycine methyltransferase fromHalorhodospira 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 Å resolution and the orthorhombic crystal diffracted to 1.8 Å resolution.

A simplified characterization of S-adenosyl-l-methionine-consuming enzymes with 1-Step EZ-MTase: a universal and straightforward coupled-assay for in vitro and in vivo setting

“… 57 Little mechanistic information is available regarding this enzyme, with a handful of kinetic reports 54 , 58 , 59 and one single crystal structure of the apo-form of SDMT from Galdieria sulphuraria . 54 , 60 In an experimental tour de force, we established the pH-dependence of Gs SDMT reaction rates for sarcosine (Dixon plots; Fig. 4B ).…”

Implication of metal complexes in biology and medicine, the system cadmium (II)/iron (II)/zinc (II) – sarcosine

“…It is normally not detected in human blood or urine. Sarcosine has several biomedical applications [16][17][18][19][20] .…”