Emerging facets of prokaryotic glycosylation

Abstract

Glycosylation of proteins is one of the most prevalent post-translational modifications occurring in nature, with a wide repertoire of biological implications. Pathways for the main types of this modification, the N-and O-glycosylation, can be found in all three domains of life-the Eukarya, Bacteria and Archaea-thereby following common principles, which are valid also for lipopolysaccharides, lipooligosaccharides and glycopolymers. Thus, studies on any glycoconjugate can unravel novel facets of the still incompletely understood fundamentals of protein N-and O-glycosylation. While it is estimated that more than two-thirds of all eukaryotic proteins would be glycosylated, no such estimate is available for prokaryotic glycoproteins, whose understanding is lagging behind, mainly due to the enormous variability of their glycan structures and variations in the underlying glycosylation processes. Combining glycan structural information with bioinformatic, genetic, biochemical and enzymatic data has opened up an avenue for in-depth analyses of glycosylation processes as a basis for glycoengineering endeavours. Here, the common themes of glycosylation are conceptualised for the major classes of prokaryotic (i.e. bacterial and archaeal) glycoconjugates, with a special focus on glycosylated cell-surface proteins. We describe the current knowledge of biosynthesis and importance of these glycoconjugates in selected pathogenic and beneficial microbes.

Glycosylated amyloid‐like proteins in the structural extracellular polymers of aerobic granular sludge enriched with ammonium‐oxidizing bacteria

“…Overall, protein glycosylation is an energetically costly cellular process. Approximately 2% of the human genome encodes proteins involved in glycosylation events (Schäffer & Messner, ). Why AOBs produce glycosylated proteins in the EPS and how does it regulate are interesting topics for further research.…”

“…Overall, protein glycosylation is an energetically costly cellular process. Approximately 2% of the human genome encodes proteins involved in glycosylation events (Schäffer & Messner, 2017). Why…”

Flagellin Glycoproteomics of the Periodontitis Associated Pathogen Selenomonas sputigena Reveals Previously Not Described O-glycans and Rhamnose Fragment Rearrangement Occurring on the Glycopeptides

“…Unlike in mammalian glycoprotein synthesis, glycosylation pathways in bacterial species are highly diverse (21), making different orthogonal approaches a necessity to collect information on monosaccharide identity, glycan composition, and protein attachment. Mass spectrometry has always been a core technology for determining the primary structure of glycoprotein glycans.…”

Tannerella forsythiastrains display different cell-surface nonulosonic acids: biosynthetic pathway characterization and first insight into biological implications

“…It is established knowledge that Sias play crucial roles in the life-cycles of various organisms from eukaryotes to prokaryotes (Varki et al 2009). While Sias are commonly present as terminal residues of many eukaryotic glycoconjugates and have also been identified in several prokaryotic polysaccharides, a number of NulOs appear to be unique to bacterial species (Knirel et al 2003; Morrison and Imperiali 2014; Zunk and Kiefel 2014; Kenyon et al 2015; Schäffer and Messner 2016). Due to their structural and biosynthetic similarities to Sia, these NulOs are also often referred to as Sia-like sugars (Figure 1A), the most studied of which are pseudaminic acids (such as 5,7-diacetamido-3,5,7,9-tetradeoxy- l - glycero - l - manno -NulO, Pse5,7Ac 2 ) and legionaminic acids (such as 5,7-diacetamido-3,5,7,9-tetradeoxy- d - glycero - d - galacto -NulO, Leg5,7Ac 2 ).…”