title: AglF, aglG and aglI, novel members of a gene island involved in the N-glycosylation of the Haloferax volcanii S-layer glycoprotein.
abstract: Proteins in all three domains of life can experience N-glycosylation. The steps involved in the archaeal version of this post-translational modification remain largely unknown. Hence, as the next step in ongoing efforts to identify components of the N-glycosylation pathway of the halophilic archaeon Haloferax volcanii, the involvement of three additional gene products in the biosynthesis of the pentasaccharide decorating the S-layer glycoprotein was demonstrated. The genes encoding AglF, AglI and AglG are found immediately upstream of the gene encoding the archaeal oligosaccharide transferase, AglB. Evidence showing that AglF and AglI are involved in the addition of the hexuronic acid found at position three of the pentasaccharide is provided, while AglG is shown to contribute to the addition of the hexuronic acid found at position two. Given their proximities in the H. volcanii genome, the transcription profiles of aglF, aglI, aglG and aglB were considered. While only aglF and aglI share a common promoter, transcription of the four genes is co-ordinated, as revealed by determining transcript levels in H. volcanii cells raised in different growth conditions. Such changes in N-glycosylation gene transcription levels offer additional support for the adaptive role of this post-translational modification in H. volcanii.
authors.affiliation: Department of Life Sciences, Ben Gurion University, Beersheva 84105, Israel.
authors.forename: Sophie
authors.initials: S
authors.lastname: Yurist-Doutsch
authors.forename: Mehtap
authors.initials: M
authors.lastname: Abu-Qarn
authors.forename: Francesca
authors.initials: F
authors.lastname: Battaglia
authors.forename: Howard R
authors.initials: HR
authors.lastname: Morris
authors.forename: Paul G
authors.initials: PG
authors.lastname: Hitchen
authors.forename: Anne
authors.initials: A
authors.lastname: Dell
authors.forename: Jerry
authors.initials: J
authors.lastname: Eichler
mesh_terms: D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D019848:Gene Expression Regulation, Archaeal; D006031:Glycosylation; D019622:Haloferax volcanii / Q000235:genetics* / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D050296:Microbial Viability; D011401:Promoter Regions, Genetic; D017384:Sequence Deletion; D014158:Transcription, Genetic
chemical_list: D019843:Archaeal Proteins; D008562:Membrane Glycoproteins; C055764:S-layer proteins