2. Academic Validation
  3. Chemoenzymatic Synthesis of Chito-oligosaccharides with Alternating N-d-Acetylglucosamine and d-Glucosamine

Chemoenzymatic Synthesis of Chito-oligosaccharides with Alternating N-d-Acetylglucosamine and d-Glucosamine

  • Biochemistry. 2020 Dec 8;59(48):4581-4590. doi: 10.1021/acs.biochem.0c00839.
Rianne A G Harmsen 1,  Berit Bjugan Aam 1,  Jogi Madhuprakash 1 2,  Anne Grethe Hamre 1,  Ethan D Goddard-Borger 3 4 5,  Stephen G Withers 5,  Vincent G H Eijsink 1,  Morten Sørlie 1
Affiliations

Affiliations

  • 1 Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, PO 5003, N-1432 Ås, Norway.
  • 2 Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, India.
  • 3 Walter & Eliza Hall, Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, Australia.
  • 4 Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia.
  • 5 Department of Chemistry, University of British Colombia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
PMID: 33213137 DOI: 10.1021/acs.biochem.0c00839
Abstract

Chito-oligosaccharides (CHOS) are homo- or hetero-oligomers of N-acetylglucosamine (GlcNAc, A) and d-glucosamine (GlcN, D). Production of well-defined CHOS-mixtures, or even pure CHOS, with specific lengths and sugar compositions, is of great interest since these oligosaccharides have interesting bioactivities. While direct chemical synthesis of CHOS is not straightforward, chemo-enzymatic approaches have shown some promise. We have used engineered glycoside hydrolases to catalyze oligomerization of activated DA building blocks through transglycosylation reactions. The building blocks were generated from readily available (GlcNAc)2-para-nitrophenol through deacetylation of the nonreducing end sugar with a recombinantly expressed deacetylase from Aspergillus niger (AnCDA9). This approach, using a previously described hyper-transglycosylating variant of ChiA from Serratia marcescens (SmChiA) and a newly generated transglycosylating variant of Chitinase D from Serratia proteamaculans (SpChiD), led to production of CHOS containing up to ten alternating D and A units [(DA)2, (DA)3, (DA)4, and (DA)5]. The most abundant compounds were purified and characterized. Finally, we demonstrate that (DA)3 generated in this study may serve as a specific inhibitor of the human chitotriosidase. Inhibition of this enzyme has been suggested as a therapeutic strategy against systemic sclerosis.

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