Frontiers in Chemistry (May 2022)

Chemoenzymatic Synthesis of Asymmetrically Branched Human Milk Oligosaccharide Lacto-N-Hexaose

  • Kai-Eng Ooi,
  • Xiu-Wen Zhang,
  • Cheng-Yu Kuo,
  • Ying-Jia Liu,
  • Ching-Ching Yu,
  • Ching-Ching Yu

DOI
https://doi.org/10.3389/fchem.2022.905105
Journal volume & issue
Vol. 10

Abstract

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We herein reported the first chemoenzymatic synthesis of lacto-N-hexaose (LNH) by combining chemical carbohydrate synthesis with a selectively enzymatic glycosylation strategy. A tetrasaccharide core structure GlcNH2β1→3 (GlcNAcβ1→6) Galβ1→4Glc, a key precursor for subsequent enzymatic glycan extension toward asymmetrically branched human milk oligosaccharides, was synthesized in this work. When the order of galactosyltransferase-catalyzed reactions was appropriately arranged, the β1,4-galactosyl and β1,3-galactosyl moieties could be sequentially assembled on the C6-arm and C3-arm of the tetrasaccharide, respectively, to achieve an efficient LNH synthesis. Lacto-N-neotetraose (LNnH), another common human milk oligosaccharide, was also synthesized en route to the target LNH.

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