title: N-linked glycosylation in Archaea: two paths to the same glycan.
abstract: N-linked protein glycosylation occurs in all three branches of life, eukaryotes, bacteria and archaea. The simplest system is that of the bacterium, Campylobacter jejuni, in which a heptasaccharide glycan is added to multiple proteins from a single lipid carrier molecule. In the eukaryotic system a conserved tetradecasaccharide modification is first added to target proteins, but is then modified by trimming and addition of other glycans from additional carrier molecules resulting in a diverse array of glycans of distinct functionality. In the halophilic Archaea from the Dead Sea, Haloferax volcanii, the surface array or S-layer protein is glycosylated with a pentasaccharide. This glycan is synthesized from two separate carrier molecules, one that carries a tetrasaccharide and another that carries the terminal mannose, in a process that is analogous to that of eukaryotes. In this issue of Molecular Microbiology the glycosylation of the S-layer of another halophilic Archaea from the Dead Sea, Haloarcula marismortui is characterized (Calo et al., 2011). This S-layer is glycosylated with the same pentasaccharide as that of Hfx.  volcanii, but the intact pentasaccharide is synthesized on a single carrier molecule in Har. marismortui in a process that more closely resembles that of the bacterial N-linked system.
authors.affiliation: Enteric Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA. guerry@med.navy.mil
authors.forename: Patricia
authors.initials: P
authors.lastname: Guerry
mesh_terms: D019843:Archaeal Proteins / Q000378:metabolism*; D019614:Haloarcula marismortui / Q000378:metabolism*; D019622:Haloferax volcanii / Q000378:metabolism*
chemical_list: D019843:Archaeal Proteins