AglR is required for addition of the final mannose residue of the N-linked glycan decorating the Haloferax volcanii S-layer glycoprotein.

Journal Article (Journal Article)

BACKGROUND: Recent studies of Haloferax volcanii have begun to elucidate the steps of N-glycosylation in Archaea, where this universal post-translational modification remains poorly described. In Hfx. volcanii, a series of Agl proteins catalyzes the assembly and attachment of a N-linked pentasaccharide to the S-layer glycoprotein. Although roles have been assigned to the majority of Agl proteins, others await description. In the following, the contribution of AglR to N-glycosylation was addressed. METHODS: A combination of bioinformatics, gene deletion, mass spectrometry and metabolic radiolabeling served to show a role for AglR in archaeal N-glycosylation at both the dolichol phosphate and reporter glycoprotein levels. RESULTS: The modified behavior of the S-layer glycoprotein isolated from cells lacking AglR points to an involvement of this protein in N-glycosylation. In cells lacking AglR, glycan-charged dolichol phosphate, including mannose-charged dolichol phosphate, accumulates. At the same time, the S-layer glycoprotein does not incorporate mannose, the final subunit of the N-linked pentasaccharide decorating this protein. AglR is a homologue of Wzx proteins, annotated as flippases responsible for delivering lipid-linked O-antigen precursor oligosaccharides across the bacterial plasma membrane during lipopolysaccharide biogenesis. CONCLUSIONS: The effects resulting from aglR deletion are consistent with AglR interacting with dolichol phosphate-mannose, possibly acting as a dolichol phosphate-mannose flippase or contributing to such activity. GENERAL SIGNIFICANCE: Little is known of how lipid-linked oligosaccharides are translocated across membrane during N-glycosylation. The possibility of Hfx. volcanii AglR mediating or contributing to flippase activity could help address this situation.

Full Text

Duke Authors

Cited Authors

  • Kaminski, L; Guan, Z; Abu-Qarn, M; Konrad, Z; Eichler, J

Published Date

  • October 2012

Published In

Volume / Issue

  • 1820 / 10

Start / End Page

  • 1664 - 1670

PubMed ID

  • 22750201

Pubmed Central ID

  • PMC3572504

International Standard Serial Number (ISSN)

  • 0006-3002

Digital Object Identifier (DOI)

  • 10.1016/j.bbagen.2012.06.014


  • eng

Conference Location

  • Netherlands