title: Effect of C-terminal domain truncation of Thermus thermophilus trehalose synthase on its substrate specificity.
abstract: The C-terminal domain of the three-domain-comprising trehalose synthase from Thermus thermophilus was truncated in order to study the effect on the enzyme's activity and substrate specificity. Compared with the wild-type (WT) enzyme, the two truncated enzymes (DM1 and DM2) showed lower maltose- and trehalose-converting activities and a different transglycosylation reaction mechanism. In the mutants, the glucose moiety cleaved from the maltose substrate was released from the enzyme and intercepted by external glucose oxidase, preventing the production of trehalose. The WT enzyme, however, retained the glucose in the active site to effectively produce trehalose. In addition, DM1 synthesized much higher amounts of mannose-containing disaccharide trehalose analog (Man-TA) than did the WT and DM2. The results suggest that the C-terminal domain in the WT enzyme is important for retaining the glucose moiety within the active site. The mutant enzymes could be used to produce Man-TA, a postulated inhibitor of gut disaccharidases.
authors.affiliation: Department of Food and Nutrition, Brain Korea 21 Project, Yonsei University, Seoul 120-749, Republic of Korea.
authors.forename: Chang-Bae
authors.initials: CB
authors.lastname: Cho
authors.affiliation: Department of Food and Nutrition, Brain Korea 21 Project, Yonsei University, Seoul 120-749, Republic of Korea.
authors.forename: Da-Yeon
authors.initials: DY
authors.lastname: Park
authors.affiliation: Department of Food and Nutrition, Brain Korea 21 Project, Yonsei University, Seoul 120-749, Republic of Korea. Electronic address: soobok@yonsei.ac.kr.
authors.forename: Soo-Bok
authors.initials: SB
authors.lastname: Lee
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain / Q000235:genetics; D004187:Disaccharides / Q000378:metabolism; D005964:Glucosyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006031:Glycosylation; D007218:Industrial Microbiology; D007700:Kinetics; D008320:Maltose / Q000378:metabolism; D000072417:Protein Domains; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D013379:Substrate Specificity; D016963:Thermus thermophilus / Q000201:enzymology* / Q000235:genetics; D014199:Trehalose / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004187:Disaccharides; D011994:Recombinant Proteins; D008320:Maltose; D014199:Trehalose; D005964:Glucosyltransferases; C099692:trehalose synthase
keywords: Mannose-containing disaccharide trehalose analog; Thermus thermophilus; Trehalose; Trehalose synthase; Truncation