Haloferax volcanii N-Glycosylation: Delineating the Pathway of dTDP-rhamnose Biosynthesis Academic Article uri icon

abstract

  • In the halophilic archaea Haloferax volcanii, the surface (S)-layer glycoprotein can be modified by two distinct N-linked glycans. The tetrasaccharide attached to S-layer glycoprotein Asn-498 comprises a sulfated hexose, two hexoses and a rhamnose. While Agl11-14 have been implicated in the appearance of the terminal rhamnose subunit, the precise roles of these proteins have yet to be defined. Accordingly, a series of in vitro assays conducted with purified Agl11-Agl14 showed these proteins to catalyze the stepwise conversion of glucose-1-phosphate to dTDP-rhamnose, the final sugar of the tetrasaccharide glycan. Specifically, Agl11 is a glucose-1-phosphate thymidylyltransferase, Agl12 is a dTDP-glucose-4, 6-dehydratase and Agl13 is a dTDP-4-dehydro-6-deoxy- glucose-3, 5-epimerase, while Agl14 is a dTDP-4-dehydrorhamnose reductase. Archaea …

publication date

  • May 1, 2014