Identifying Components of a Halobacterium salinarum N-Glycosylation Pathway

Abstract

Whereas N-glycosylation is a seemingly universal process in Archaea, pathways of N-glycosylation have only been experimentally verified in a mere handful of species. Toward expanding the number of delineated archaeal N-glycosylation pathways, the involvement of the putative Halobacterium salinarum glycosyltransferases VNG1067G, VNG1066C, and VNG1062G in the assembly of an N-linked tetrasaccharide decorating glycoproteins in this species was addressed. Following deletion of each encoding gene, the impact on N-glycosylation of the S-layer glycoprotein and archaellins, major glycoproteins in this organism, was assessed by mass spectrometry. Likewise, the pool of dolichol phosphate, the lipid upon which this glycan is assembled, was also considered in each deletion strain. Finally, the impacts of such deletions were characterized in a series of biochemical, structural and physiological assays. The results revealed that VNG1067G, VNG1066C, and VNG1062G, renamed Agl25, Agl26, and Agl27 according to the nomenclature used for archaeal N-glycosylation pathway components, are responsible for adding the second, third and fourth sugars of the N-linked tetrasaccharide decorating Hbt. salinarum glycoproteins. Moreover, this study demonstrated how compromised N-glycosylation affects various facets of Hbt. salinarum cell behavior, including the transcription of archaellin-encoding genes.

Influence of N-Glycosylation on Virus–Host Interactions in Halorubrum lacusprofundi

“…lacusprofundi S-layer [ 41 , 69 ], as previously shown for both Hfx. volcanii [ 15 ] and Halobacterium salinarum [ 9 ]. To gain insight into the relationship between N-glycosylation and viral infection, we used the ∆ aglB mutant to analyze the importance of this post-translational modification on the life cycle of PVs and two viruses with different lifestyles infecting this species ( Table 1 ).…”

“…In halophilic Archaea (haloarchaea), Archaea that thrive in environments characterized by high salt concentrations, N-glycosylation is important for protein folding, stability, and function [ 2 , 7 , 8 , 9 ]. For example, N-glycosylation of the surface (S)-layer glycoprotein, comprising the protein envelope of haloarchaeal cells, is important for cell stability.…”