Biosynthesis and Role of N-Linked Glycosylation in Cell Surface Structures of Archaea with a Focus on Flagella and S Layers

Table 1

Comparison of N-glycosylation in the three domains.

Trait	Eukarya	Bacteria	Archaea
Linking sugar	GlcNAc	Di-acetyl-bacillosamine	GlcNAc, GalNAc, Glucose
Lipid carrier	Dolichol-PP	Undecaprenol-PP	Dolichol-PP, Dolichol-P
Flippase	Rft1; ATP-independent (Role of Rft questioned)	PglK ATP-dependent	Unknown
Sequon in target protein	N-X-S/T (X not P)	D/E-Z-N-X-S/T (Z, X not P)	N-X-S/T (X not P), N-X-N/L/V (X not P)
Oligosaccharyl- transferase	STT3 subunit of multimeric complex	PglB single subunit (Stt3 homologue)	AglB single subunit (Stt3 homologue)
Oligosaccharyl- transferase catalytic type	E-type	B-type	A, B, and E-type
Site of assembly of glycan	Cytosolic face of ER membrane	Cytoplasmic face of cytoplasmic membrane	Cytoplasmic face of cytoplasmic membrane
Site of glycan transfer	Lumenal face of ER membrane	External face of cytoplasmic membrane	External face of cytoplasmic membrane