Introducing N-glycans into natural products through a chemoenzymatic approach

Carbohydr Res. 2008 Nov 24;343(17):2903-13. doi: 10.1016/j.carres.2008.08.033. Epub 2008 Sep 9.

Abstract

The present study describes an efficient chemoenzymatic method for introducing a core N-glycan of glycoprotein origin into various lipophilic natural products. It was found that the endo-beta-N-acetylglucosaminidase from Arthrobactor protophormiae (Endo-A) had broad substrate specificity and can accommodate a wide range of glucose (Glc)- or N-acetylglucosamine (GlcNAc)-containing natural products as acceptors for transglycosylation, when an N-glycan oxazoline was used as a donor substrate. Using lithocholic acid as a model compound, we have shown that introduction of an N-glycan could be achieved by a two-step approach: chemical glycosylation to introduce a monosaccharide (Glc or GlcNAc) as a handle, and then Endo-A catalyzed transglycosylation to accomplish the site-specific N-glycan attachment. For those natural products that already carry terminal Glc or GlcNAc residues, direct enzymatic transglycosylation using sugar oxazoline as the donor substrate was achievable to introduce an N-glycan. It was also demonstrated that simultaneous double glycosylation could be fulfilled when the natural product contains two Glc residues. This chemoenzymatic method is concise, site-specific, and highly convergent. Because N-glycans of glycoprotein origin can serve as ligands for diverse lectins and cell-surface receptors, introduction of a defined N-glycan into biologically significant natural products may bestow novel properties onto these natural products for drug discovery and development.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acetylglucosamine / chemistry
  • Acetylglucosamine / metabolism
  • Biological Products / biosynthesis
  • Biological Products / chemistry
  • Carbohydrate Conformation
  • Glycoproteins / biosynthesis
  • Glycoproteins / chemistry
  • Glycoproteins / metabolism
  • Glycoside Hydrolases / metabolism
  • Glycosides / chemistry
  • Glycosylation
  • Indicators and Reagents
  • Models, Molecular
  • Monosaccharides / metabolism
  • Oxazolone / analogs & derivatives
  • Oxazolone / chemistry
  • Polysaccharides / chemistry*
  • Polysaccharides / metabolism*

Substances

  • Biological Products
  • Glycoproteins
  • Glycosides
  • Indicators and Reagents
  • Monosaccharides
  • Polysaccharides
  • trifluoromethyloxazolinone
  • Oxazolone
  • Glycoside Hydrolases
  • Acetylglucosamine