title: Biosynthesis of glucosyl glycerol, a compatible solute, using intermolecular transglycosylation activity of amylosucrase from Methylobacillus flagellatus KT.
abstract: A putative α-amylase gene (accession number, CP000284) of Methylobacillus flagellatus KT ATCC51484 was cloned in Escherichia coli, and its gene product was expressed and characterized. The purified recombinant enzyme (MFAS) displayed a typical amylosucrase (ASase) activity by the demonstration of multiple activities of hydrolysis, isomerization, and polymerization although it was designated as an α-amylase. The optimal reaction temperature and pH for the sucrose hydrolysis activity of MFAS were determined to be 45 °C and pH 8.5, respectively. MFAS has relatively high thermostable characteristics compared with other ASases, as demonstrated by a half-life of 19.3 min at 50 °C. MFAS also showed polymerization activity using sucrose as a sole substrate. Glycerol was transglycosylated by the intermolecular transglycosylation activity of MFAS. Two major products were observed by thin-layer chromatography and isolated by paper chromatography and recycling HPLC. Using (1)H and (13)C NMR, their chemical structures were determined to be (2S)-1-O-α-D-glucosyl-glycerol or (2R)-1-O-α-D-glucosyl-glycerol and 2-O-α-D-glucosyl-glycerol, in which a glucose molecule is linked to glycerol via an α-glycosidic linkage.
authors.affiliation: Graduate School of Biotechnology and Institute of Life Science and Resources, Kyung Hee University, Yongin, 446-701, South Korea.
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Jeong
authors.forename: Dong-Ho
authors.initials: DH
authors.lastname: Seo
authors.forename: Jong-Hyun
authors.initials: JH
authors.lastname: Jung
authors.forename: Ji-Hae
authors.initials: JH
authors.lastname: Park
authors.forename: Nam-In
authors.initials: NI
authors.lastname: Baek
authors.forename: Myo-Jeong
authors.initials: MJ
authors.lastname: Kim
authors.forename: Cheon-Seok
authors.initials: CS
authors.lastname: Park
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D005960:Glucosides / Q000096:biosynthesis*; D005964:Glucosyltransferases / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D020631:Methylobacillus / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D005960:Glucosides; C034727:glucosylglycerol; D005964:Glucosyltransferases; C019700:amylosucrase