Fig. 4: Sequence and structure analysis of extended and truncated Alteromonas phage tail fibers and their chaperones.

MultAlin-generated⁷⁴ sequence alignments of the four tail fibers (a) and chaperones (b) with the knob domain(s) flanking residues S1 and S2 of the tail fibers and the twisted β-hairpin extension of the chaperones highlighted, respectively. c Ribbon diagrams of full-length, homotrimeric tail fibers predicted using AlphaFold-Multimer. The tail fibers present a conserved domain architecture including an N-terminal shoulder domain, followed by the stem, neck, knob, and distal head domains (the latter assumed to feature the receptor binding sites for host receptor interactions). Arrows indicate residues S1 (green) and S2 (brown) of conserved flanking sequences of the central knob region for all tail fibers. An insertion in this region results in a knob duplication for the A5 (gp8) and GOV_bin_2917 (gp51) tail fibers. d Ribbon diagrams of monomeric, full-length chaperones predicted using AlphaFold 2.0. The chaperones have a conserved architecture except for the twisted β-hairpin extensions (blue) for chaperones A5 gp9 and GOV_bin_2917 gp50. Model confidence scores are provided in Table S1. Source Data (.pdb files) are provided as a Source Data file.