title: Different routes to the same ending: comparing the N-glycosylation processes of Haloferax volcanii and Haloarcula marismortui, two halophilic archaea from the Dead Sea.
abstract: Recent insight into the N-glycosylation pathway of the haloarchaeon, Haloferax volcanii, is helping to bridge the gap between our limited understanding of the archaeal version of this universal post-translational modification and the better-described eukaryal and bacterial processes. To delineate as yet undefined steps of the Hfx. volcanii N-glycosylation pathway, a comparative approach was taken with the initial characterization of N-glycosylation in Haloarcula marismortui, a second haloarchaeon also originating from the Dead Sea. While both species decorate the reporter glycoprotein, the S-layer glycoprotein, with the same N-linked pentasaccharide and employ dolichol phosphate as lipid glycan carrier, species-specific differences in the two N-glycosylation pathways exist. Specifically, Har. marismortui first assembles the complete pentasaccharide on dolichol phosphate and only then transfers the glycan to the target protein, as in the bacterial N-glycosylation pathway. In contrast, Hfx. volcanii initially transfers the first four pentasaccharide subunits from a common dolichol phosphate carrier to the target protein and only then delivers the final pentasaccharide subunit from a distinct dolichol phosphate to the N-linked tetrasaccharide, reminiscent of what occurs in eukaryal N-glycosylation. This study further indicates the extraordinary diversity of N-glycosylation pathways in Archaea, as compared with the relatively conserved parallel processes in Eukarya and Bacteria.
authors.affiliation: Department of Life Sciences, Ben Gurion University of the Negev, Beersheva 84105, Israel.
authors.forename: Doron
authors.initials: D
authors.lastname: Calo
authors.forename: Ziqiang
authors.initials: Z
authors.lastname: Guan
authors.forename: Shai
authors.initials: S
authors.lastname: Naparstek
authors.forename: Jerry
authors.initials: J
authors.lastname: Eichler
mesh_terms: D059001:Aquatic Organisms / Q000378:metabolism; D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D004288:Dolichol Phosphates / Q000378:metabolism; D019848:Gene Expression Regulation, Archaeal; D006031:Glycosylation; D019614:Haloarcula marismortui / Q000378:metabolism*; D019622:Haloferax volcanii / Q000378:metabolism*; D008562:Membrane Glycoproteins; D011499:Protein Processing, Post-Translational; D012623:Seawater; D016415:Sequence Alignment
chemical_list: D019843:Archaeal Proteins; D004288:Dolichol Phosphates; D008562:Membrane Glycoproteins; C055764:S-layer proteins