Phage Tail–Like Bacteriocins

Many dsDNA bacterial viruses (bacteriophages/phages) have long tail structures that serve as organelles for DNA delivery to host targets. These structures, particularly those of Myoviridae and Siphoviridae phages, have an evolutionary relationship with other cellular biological entities that share the common function of penetrating the bacterial envelope. Among these are type VI secretion systems, insecticidal protein complexes, and bacteriocins. Phage tail-like bacteriocins (PTLBs) are widespread in bacteria, comprising different types that likely evolved independently. They can be divided into two major classes: the R-type PTLBs, which are related to contractile Myoviridae phage tails, and the F-type PTLBs, which are related to noncontractile Siphoviridae phage tails. This review provides an overview of the history, biology, and diversity of these entities and also covers recent efforts to utilize these potent bactericidal agents as human therapeutics against bacterial disease.