Liang, J., Zhang, H., Tan, Y. L., Zhao, H., & Ang, E. L. (2022). Directed Evolution of Replication-Competent Double-Stranded DNA Bacteriophage toward New Host Specificity. ACS Synthetic Biology, 11(2), 634–643. https://doi.org/10.1021/acssynbio.1c00319
In the fight against antimicrobial resistance, bacteriophage is a promising alternative to antibiotics. However, due to their narrow spectrum, phage therapy requires the careful matching between host and bacteriophage to be effective. Despite our best efforts, nature remains as the only source of novel phage specificity. Directed evolution can potentially open an avenue for engineering phage specificity and improving qualities of phages that are not strongly selected for in their natural environments but are important for therapeutic applications. In this work, we present a strategy that generates large libraries of replication-competent phage variants directly from synthetic DNA fragments, with no restriction on their host specificity. Using the T7 bacteriophage as a proof-of-concept, we created a large library of tail fiber mutants with at least 107 unique variants. From this library, we identified mutants that has broadened specificity as evidenced by their novel lytic activity against Yersinia enterocolitica, a strain that the wild-type T7 was unable to lyse. Using the same concept, mutants with improved lytic efficiency and characteristics, such as lytic condition tolerance and resistance suppression, were also identified. However, the observed limitations in altering host specificity by tail fiber mutagenesis suggests that other bottlenecks could be of equal or even greater importance.
This research / project is supported by the A*STAR - HBMS - IAF-PP, (Wound Care Innovation for the Tropics)
Grant Reference no. : H17/01/a0/0V9
This research / project is supported by the A*STAR - JCO Visiting Investigatorship Program
Grant Reference no. : 1535j00137