N‐Linked Glycans of Chloroviruses Sharing a Core Architecture without Precedent. Issue 2 (19th November 2015) - De Castro, Cristina
Abstract: N‐glycosylation is a fundamental modification of proteins and exists in the three domains of life and in some viruses, including the chloroviruses, for which a new type of core N‐glycan is herein described. This N‐glycan core structure, common to all chloroviruses, is a pentasaccharide with a β‐glucose linked to an asparagine residue which is not located in the typical sequon N‐X‐T/S. The glucose is linked to a terminal xylose unit and a hyperbranched fucose, which is in turn substituted with a terminal galactose and a second xylose residue. The third position of the fucose unit is always linked to a rhamnose, which is a semiconserved element because its absolute configuration is virus‐dependent. Additional decorations occur on this core N‐glycan and represent a molecular signature for each chlorovirus. Abstract : Glycan signature : Chloroviruses glycosylate their capsid protein in a host‐independent process. These N‐linked glycans have unprecedented structures, and each is virus‐specific, but all share the same core motif. Conservation in the core region occurs at two different levels: the most conserved region comprises five residues and inclusion of the sixth extends this strictly conserved core. This core oligosaccharide represents a new type of N‐glycosylation.