Design and utilization of chitinases with low hydrolytic activities

Michinari Kohri, Atsushi Kobayashi, Shinichiro Shoda

Research output: Contribution to journalShort survey

3 Citations (Scopus)

Abstract

Enzymatic glycosylation reactions by combined use of activated donor substrates and deactivated enzymes have been reviewed. Glycosidase-catalyzed transglycosylation reaction of sugar oxazolines to various glycosyl acceptors have successfully been achieved for the formation of poly-and oligo- saccharides such as chitin, glycosaminoglycans, and the core trisaccharide of N-linked oligosaccharide. These reactions proceeded efficiently using appropriate glycosidases under basic conditions, where the enzymes showed lower hydrolytic activity toward their natural substrates. In order to realize the transglycosylation reactions under neutral conditions, several mutants chitinase A1 from Bacillus circulans WL-12 were constructed. Some of mutants were found to be efficient for transglycosylation under neutral conditions. These reactions could be applied to the stepwise synthesis of oligosaccharides and oligosaccharide-containing macromonomers. Novel thermosensitive polymers carrying oligosaccharides have successfully been synthesized by the radical copolymerization of the resulting macromonomers with N-isopropylacrylamide. One-pot chemo-enzymatic synthesis of oligosaccharides starting from a free sugar has been demonstrated via a sugar oxazoline intermediate formed in situ and the subsequent enzymatic transglycosylation. This novel technique of transferring an oligosaccharide moiety having an N-acetylhexosamine unit is a promising tool to pave the way to the new generation of oligosaccharide synthesis.

Original languageEnglish
Pages (from-to)165-180
Number of pages16
JournalTrends in Glycoscience and Glycotechnology
Volume19
Issue number107
DOIs
Publication statusPublished - 2007 May 1

Keywords

  • Chitinase
  • Site-directed mutagenesis
  • Sugar oxazoline
  • Transition-state analogue

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry

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