ABSTRACT
Bacteriophages, with their intricate and highly specialized structures, represent some of the most fascinating architectures in the biological world. These viral entities serve as a sustainable and eco-friendly alternative to chemical treatments in agriculture and as biocontrol agents against bacterial pathogens. Despite their promise, the structural intricacies of phages remain poorly understood, limiting their application in phage therapy.

Using cryo-electron microscopy, we resolved the structures of two bacteriophages, ϕTE and Bas63, both featuring long contractile tails. Our findings reveal remarkable architectural features, including a unique neck topology where a tail terminator protein compensates for reduced connectivity between sheath subunits. We also uncovered complex interactions among tail fibers, sheath initiator proteins, and baseplate wedge proteins, providing insights into host recognition mechanisms and the process of tail contraction. Notably, we identified two distinct oligomeric states of the tape measure protein (TMP), suggesting proteolytic processing. These discoveries advance our understanding of phage-host interactions and offer a structural blueprint for the rational design of phages tailored for biocontrol applications in agriculture.

BIOGRAPHY
Mihnea Bostina is an Associate Professor in the Department of Microbiology and Immunology at the University of Otago, where he also serves as the Academic Lead of the Electron Microscopy Unit at the Otago Micro and Nano Imaging Center. He holds an MSc from Bucharest University, Romania, and a PhD in Biophysics from the Max Planck Institute and Goethe University in Frankfurt, Germany. After completing postdoctoral research at Harvard Medical School and McGill University, he joined the University of Otago in 2013.

The Bostina Lab focuses on viral structures and virus-host interactions using advanced electron microscopy (EM) techniques. His group studies a diverse range of viruses, including oncolytic viruses like Senecavirus, SARS-related coronaviruses, bacteriophages, and wildlife viruses affecting endangered species. His work on bacteriophages has uncovered unique structural features, such as tail contraction mechanisms and proteolytic processing, advancing their potential in biocontrol and phage therapy. Dr. Bostina’s research bridges fundamental virology with practical applications, contributing to the development of innovative antiviral strategies and biotechnological tools.