A novel type of N-glycoside linkage, Asn-Glc, has recently been described (Wieland et al, 1983), which occurs in the cell surface glycoprotein of the archaebacterium Halobacterium halobium. Sulfated oligosaccharides containing glucuronic acid (and, within some of the oligosaccharides, iduronic acid) are bound via a glucose residue to Asn residues in the cell surface glycoprotein. Lipid-linked precursors of this type of glycoconjugates (Lechner et al., 1985 a) exhibit the following unusual features: The carrier lipid is a C60-dolichol rather than a bacterial undecaprenol. Sulfation of the saccharides is completed whilst they are linked to the lipid, and does not occur after transfer of the saccharides to the protein. The sulfated oligosaccharide is bound to the dolichol via a monophosphate rather than a pyrophosphate bridge. Some lipid oligosaccharides contain an additional 3-0-methylglucose residue (Lechner et al., 1985 b). This methylated sugar is peripherally linked to the lipid-saccharide intermediates and occurs exclusively at the lipid linked level, but is absent when the oligosaccharide is linked to protein. When S-adenosylmethionine-dependent methylation of this glucose residue is inhibited in vivo in halobacteria, sulfated glycoprotein synthesis is depressed as well. From these data, we conclude that transient methylation of sulfated lipid oligosaccharides is a prerequisite for the transfer of the saccharide moiety to the acceptor proteins, such as the cell surface glycoprotein and the flagellins.