Bacteriophage module reshuffling results in adaptive host range as exemplified by the baseplate model of listerial phage A118

Each phage infects its specific bacterial host strain through highly specific interactions between the baseplate-associated receptor binding protein (RBP) at the tip of the phage tail and the receptor at the host surface. Baseplates incorporate structural core modules, Dit and Tal, largely conserved among phages, and peripheral modules anchoring the RBPs. Exploiting structural information from the HHpred program and EM data from the Bielmann et al. (2015) paper, a molecular model of the A118 phage baseplate was generated from different building blocks. This model implies the occurrence of baseplate module reshuffling and suggests that listerial phage A118 may have been derived from lactococcal phage TP901-1 through host species exchange. With the increase of available viral module structures, modelling phage baseplates will become easier and more reliant, and will provide insightful information on the nature of the phage host receptor and its mode of recognition.