Fig. 4: Conservation and divergence of the N-terminal helical bundles.
From: The structures of two archaeal type IV pili illuminate evolutionary relationships
a Sequence alignments of the N-terminal long helix in three archaeal flagellins, one archaeal “adhesion” protein, three archaeal T4P and three bacterial T4P. Area where the bacterial T4P N-terminal helix melts is indicated by two red arrows. b Helical symmetries of the filaments mentioned in a, with archaeal filaments light blue and bacterial filaments orange. c Five adjacent N-terminal helices of P. arsenaticum pilins, S. solfataricus pilins, I. hospitalis proteins, M. hungatei flagellins and N. gonorrhoeae pilins are shown. The Cα trace is shown in cartoon (left), with one helix colored cyan and the other four colored yellow. The bundles are also shown in an atomic surface view and colored by lipophilicity (right). d All-against-all comparison of the five helix bundles of the structures shown in a. The matrix is based on the pairwise RMSD comparisons calculated from PyMOL.
