Synthesis of the Highly Branched Hexasaccharide Core of Chlorella Virus N‐Linked Glycans

Abstract

Chlorella viruses produce N‐linked glycoproteins with carbohydrate moieties that differ in structure from all other N‐linked glycans. In addition, unlike most viruses, these organisms do not hijack the biosynthetic machinery of the host to make glycocoproteins; instead, they produce their own carbohydrate‐processing enzymes. A better understanding of the function and assembly of these fascinating and structurally‐unprecedented glycans requires access to probe molecules. This work describes the first synthesis of a chlorella virus N‐linked glycan, a highly branched hexasaccharide that contains the pentasaccharide present in all of the >15 structures reported to date. The target molecule includes a glucosyl‐asparagine linkage and a “hyperbranched” fucose residue in which all of the hydroxyl groups are glycosylated. Both convergent and linear approaches were investigated with the latter being successful in providing the target in 16 steps and 13 % overall yield.

Chlorovirus PBCV-1 protein A064R has three of the transferase activities necessary to synthesize its capsid protein N-linked glycans

“…The synthesis of 1 and 6 is described in the SI Appendix (Synthesis, SI Appendix, Figs. S19-S21) and followed protocols previously reported (42).…”

Preise von CSC und CIC 2019

“…Besonderes Augenmerk ist dabei auf mikrobielle Glykane einschließlich solcher aus Bakterien, Viren und Pilzen gerichtet. Er beschrieb die Synthese der Wiederholungseinheit aus einem Kapselpolysaccharid eines Campylobacter jejuni in der Angewandte Chemie und die Synthese des zentralen Hexasaccharids in N‐verknüpften Glykanen von Chlorella ‐Viren in Chemistry—A European Journal . Lowary ist seit 2011 Mitglied des Redaktionsbeirats von ChemistryOpen .…”

CSC and CIC Awards 2019

“…Lowary's research is focused on the synthesis of complex glycans as biological probes with a particular emphasis on microbial glycans including those from bacteria, viruses, and fungi. He has reported on the synthesis of a Campylobacter jejuni capsular polysaccharide repeating unit in Angewandte Chemie and on the synthesis of the hexasaccharide core of Chlorella virus N‐linked glycans in Chemistry—A European Journal . Lowary has been on the Editorial Board of ChemistryOpen since 2011.…”