Sequence and structural alignment of the predicted S144 tail fiber protein. (a) Sequence alignment of the C-terminal residues of the tail fibers from phages S144, GAP31, GAP32 and Mu G+. (b) Structural comparison by superposition of the experimental resolved tail fiber protein from phage Mu G+ (red; PDBID:5YVQ) and the predicted S144 tail fiber (blue) (RMSD 1,2 Å over 348 matched residues, TM-score 0.843) with the three domains determined in Mu’s tail fiber, (c) from the distal end and (d) zoom in of the C-terminus, involved in the cell surface binding. The arrows indicate structural differences between the two tail fibers.