Protein engineering of Sulfolobus solfataricus maltooligosyltrehalose synthase to alter its selectivity.
Maltooligosyltrehalose synthase (MTSase) is one of the key enzymes involved in trehalose production from starch and catalyzes an intramolecular transglycosylation reaction by converting the alpha-1,4- to alpha,alpha-1,1-glucosidic linkage. Mutations at residues F206, F207, and F405 were constructed to change the selectivity of the enzyme because the changes in selectivity could reduce the side hydrolysis reaction of releasing glucose and thus increase trehalose production from starch. As compared with wild-type MTSase, F405Y and F405M MTSases had decreased ratios of the initial rate of glucose formation to that of trehalose formation in starch digestion at 75 degrees C when wild-type and mutant MTSases were, respectively, used with isoamylase and maltooligosyltrehalose trehalohydrolase (MTHase). The highest trehalose yield from starch digestion was by the mutant MTSase having the lowest initial rate of glucose formation to trehalose formation, and this predicted high trehalose yield better than the ratio of catalytic efficiency for hydrolysis to that for transglycosylation.
Fang
Tsuei-Yun
TY
Department of Food Science, National Taiwan Ocean University, Keelung, Taiwan. tyfang@mail.ntou.edu.tw
Tseng
Wen-Chi
WC
Pan
Ching-Hsing
CH
Chun
Yao-Te
YT
Wang
Mei-Ying
MY
D004795:Enzyme Stability; D005964:Glucosyltransferases / Q000235:genetics* / Q000378:metabolism*; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D015202:Protein Engineering; D013379:Substrate Specificity; D048229:Sulfolobus solfataricus / Q000201:enzymology*; D014199:Trehalose / Q000096:biosynthesis
D014199:Trehalose; D005964:Glucosyltransferases; C099084:maltooligosyl trehalose synthase