tailieunhanh - Báo cáo khoa học: Single amino acid residue changes in subsite ) 1 of inulosucrase from Lactobacillus reuteri 121 strongly influence the size of products synthesized

Bacterial fructansucrase enzymes belong to glycoside hydrolase family 68 and catalyze transglycosylation reactions with sucrose, resulting in the syn-thesis of fructooligosaccharides and⁄or a fructan polymer. Significant dif-ferences in fructansucrase enzyme product specificities can be observed, . | ễFEBS Journal Single amino acid residue changes in subsite - 1 of inulosucrase from Lactobacillus reuteri 121 strongly influence the size of products synthesized I OQ7 K CHimo 1 2 1 1 3 I i1 2 T h I i Q a no f1 2 Q Kí 1 I c a n Hot l l 33 rol1 3 snrl LUkdoz . OZIIIlCk OldVkO ldlj lllijo l dpei IVIdlU J. E. C. van del Ivlddlcl dliu Lubbert Dijkhuizen1 2 1 Centre for Carbohydrate Bioprocessing CCB TNO-University of Groningen Haren the Netherlands 2 Department of Microbiology Groningen Biomolecular Sciences and Biotechnology Institute GBB University of Groningen Haren the Netherlands 3 Innovative Ingredients and Products TNO Quality of Life Groningen the Netherlands Keywords inulosucrase Lactobacillus reuteri processivity site-directed mutagenesis Correspondence L. Dijkhuizen University of Groningen PO Box 14 9750 AA Haren the Netherlands Fax 31 50 3632154 Tel 31 50 3632150 E-mail Received 12 June 2006 accepted 10 July 2006 doi Bacterial fructansucrase enzymes belong to glycoside hydrolase family 68 and catalyze transglycosylation reactions with sucrose resulting in the synthesis of fructooligosaccharides and or a fructan polymer. Significant differences in fructansucrase enzyme product specificities can be observed . in the type of polymer levan or inulin synthesized and in the ratio of polymer versus fructooligosaccharide synthesis. The Lactobacillus reuteri 121 inulosucrase enzyme produces a diverse range of fructooligosaccharide molecules and a minor amount of inulin polymer with b 2-1 linkages . The three-dimensional structure of levansucrase SacB of Bacillus subtilis revealed eight amino acid residues interacting with sucrose. Sequence alignments showed that six of these eight amino acid residues including the catalytic triad D272 E523 and D424 inulosucrase numbering are completely conserved in glycoside hydrolase family 68. The other three completely conserved residues are located at the -1 subsite W271 .