Fig. 3: Glycosylation of archaeal type IV pilus and other archaeal cell appendages.
From: The structures of two archaeal type IV pili illuminate evolutionary relationships
a Violin plot showing the distributions of the serine and threonine percentages in all proteins of M. hungatei, M. maripaludis, P. furiosus, I. hospitalis, P. arsenaticum, S. solfataricus and S. islandicus. The red diamond indicates the percentage of serine+threonine in the pilin or flagellin from this species discussed in this paper. The black box indicates the interquartile range, and the central line in the box indicates the median of the data. The species for the archaeal flagellar filaments are colored in blue-ish colors, adhesion filaments in orange, and archaeal T4P in green-ish colors. b Density (magenta) due to post-translational modifications on P. arsenaticum pilin (left) and S. solfataricus pilin (right). The protein Cα backbone is colored in orange (P. arsenaticum) or yellow (S. solfataricus). The extra density is due to N-linked (Asn) or O-linked (Thr, Ser) sugars, and the residues modified are labeled. c Surface glycosylation of the P. arsenaticum pilus (left), S. solfataricus pilus (middle) and a control rod-like virus without apparent glycosylation. The control virus and the S. solfataricus pilus were purified and imaged together. All three volumes were filtered to 7 Å. The density accounted for by atomic models is colored in gray, and the extra density is colored in magenta. Three different display thresholds are shown. A small additional density appears on the surface of the virus, and this is due to several C-terminal residues that were not part of the atomic model due to disorder, and not due to glycosylation.
