Date of Award

Summer 2023

Document Type


Degree Name

Bachelor of Science (BS)




College of Science

First Advisor

Daniel C. Williams


Bacteriophages are ubiquitous viruses containing extremely diverse genomes. Many phage genomes have been bioinformatically annotated; however, many genes lack wet-bench functional characterization. Elucidating individual phage gene function via the isolation of phage-host protein interactions allows for the exploration of novel antibacterial therapies within the context of phage-host biology. Mycobacteriophage Phayonce, infecting the host Mycobacterium smegmatis, encodes two cytotoxic gene, 41 and 64, which lack an annotated function. Using a bacterial two-hybrid screen along with the construction of fusion-protein expression vectors, multiple punitive phage-host protein interactions were isolated for both genes. Once these interactions were verified and sequenced, multiple host M. smegmatis protein interacting partners were identified for gene 41 and one, unknown partner was isolated for gene 64. The host proteins identified using the screen establish a foundation for further investigation between the protein interactions between Phayonce and its host. Once such target identified for gene 41 was a prolyl oligopeptidase, which is predicted to degrade peptide bonds within the host. This may potentially be an explanation for gene 41’s observed host cytotoxicity. Elucidating the phage-host protein interactions of Phayonce’s cytotoxic genes will provide a greater understanding of phage biology, including the various ways that biology can be exploited in the development of novel antibacterial therapeutics.