The branched receptor binding complex ofAckermannviridaephages promotes adaptative host recognition

Abstract

AbstractBacteriophages may express multiple receptor binding proteins, enabling the recognition of distinct and diverse bacterial receptors for infection of a broad range of strains.Ackermannviridaephages recognize diverse O-antigens or K-antigens as receptors by expressing multiple tail spike proteins (TSPs). These TSPs interact and form a branched protein complex protruding from the baseplate attached to the distal tail. Here, we aimed to mimic the evolution of the TSP complex by studying the acquisition of new TSPs without disrupting the functionality of the complex. Using kuttervirus phage S117 as a backbone, we demonstrated the acquisition of entiretspgenes fromKuttervirusandAgtrevirusphages within theAckermannviridaefamily. A fifth TSP was designed to interact with the complex and provide new host recognition to expand the branched TSP complex. Interestingly, the acquisition oftsp5resulted in new variants of the branched TSP complex due to the exchange or deletion oftspgenes. Overall, our study provides novel insight into the development of the branched TSP complex, enablingAckermannviridaephages to adapt to new hosts.