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Altered substrate specificity of the gluco‐oligosaccharide oxidase from Acremonium strictum
Author(s) -
Foumani Maryam,
Vuong Thu V.,
Master Emma R.
Publication year - 2011
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.23149
Subject(s) - oligosaccharide , pichia pastoris , biochemistry , xylobiose , monosaccharide , chemistry , xylose , galactose , enzyme , stereochemistry , glycoside hydrolase , glycosyl , recombinant dna , fermentation , gene
A gluco‐oligosaccharide oxidase (GOOX) from Acremonium strictum type strain CBS 346.70 was cloned and expressed in Pichia pastoris . The recombinant protein, GOOX‐VN, contained fifteen amino acid substitutions compared with the previously reported A. strictum GOOX. These two enzymes share 97% sequence identity; however, only GOOX‐VN oxidized xylose, galactose, and N ‐acetylglucosamine. Besides monosaccharides, GOOX‐VN oxidized xylo‐oligosaccharides, including xylobiose and xylotriose with similar catalytic efficiency as for cello‐oligosaccharides. Of three mutant enzymes that were created in GOOX‐VN to improve substrate specificity, Y300A and Y300N doubled k cat values for monosaccharide and oligosaccharide substrates. With this novel substrate specificity, GOOX‐VN and its variants are particularly valuable for oxidative modification of cello‐ and xylo‐oligosaccharides. Biotechnol. Bioeng. 2011;108: 2261–2269. © 2011 Wiley Periodicals, Inc.