Browsing by Subject "Sulfolobus acidocaldarius"

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    Gene deletions leading to a reduction in the number of cyclopentane rings in Sulfolobus acidocaldarius tetraether lipids.
    (FEMS Microbiol Lett, 2017-11-29) Guan, Ziqiang; Delago, Antonia; Nußbaum, Phillip; Meyer, Benjamin H; Albers, Sonja-Verena; Eichler, Jerry
    The cell membrane of (hyper)thermophilic archaea, including the thermoacidophile Sulfolobus acidocaldarius, incorporate dibiphytanylglycerol tetraether lipids. The hydrophobic cores of such tetraether lipids can include up to eight cyclopentane rings. Presently, nothing is known of the biosynthesis of these rings. In the present study, a series of S. acidocaldarius mutants deleted of genes currently annotated as encoding proteins involved in sugar/polysaccharide processing were generated and their glycolipids were considered. Whereas the glycerol-dialkyl-glycerol tetraether core of a S. acidocaldarius tetraether glycolipid considered here mostly includes four cyclopentane rings, in cells where the Saci_0421 or Saci_1201 genes had been deleted, species containing zero, two or four cyclopentane rings were observed. At the same time, in cells lacking Saci_0201, Saci_0275, Saci_1101, Saci_1249 or Saci_1706, lipids containing mostly four cyclopentane rings were detected. Although Saci_0421 and Saci_1201 are not found in proximity to other genes putatively involved in lipid biosynthesis, homologues of these sequences exist in other Archaea where cyclopentane-containing tetraether lipids are found. Thus, Saci_0421 and Saci_1201 represent the first proteins described that somehow contribute to the appearance of cyclopentane rings in the core moiety of the S. acidocaldarius glycolipid considered here.
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    N-glycosylation in the thermoacidophilic archaeon Sulfolobus acidocaldarius involves a short dolichol pyrophosphate carrier.
    (FEBS Lett, 2016-09) Guan, Ziqiang; Delago, Antonia; Nußbaum, Phillip; Meyer, Benjamin; Albers, Sonja-Verena; Eichler, Jerry
    N-glycosylation is a post-translational modification that occurs across evolution. In the thermoacidophilic archaea Sulfolobus acidocaldarius, glycoproteins are modified by an N-linked tribranched hexasaccharide reminiscent of the N-glycans assembled in Eukarya. Previously, hexose-bearing dolichol phosphate was detected in a S. acidocaldarius Bligh-Dyer lipid extract. Here, we used a specialized protocol for extracting lipid-linked oligosaccharides to detect a dolichol pyrophosphate bearing the intact hexasaccharide, as well as its biosynthetic intermediates. Furthermore, evidence for N-glycosylation of two S. acidocaldarius proteins by the same hexasaccharide and its derivatives was collected. These findings thus provide novel insight into archaeal N-glycosylation.