Engineering T3 and T7 host range to target protein receptors and guide bacterial evolution.

Phage engineering holds significant potential for overcoming the challenges that limit phage therapy. A promising yet underutilized approach is engineering phage host range to target specific receptors and guiding bacterial evolution into a desirable trajectory, referred to as evolutionary steering. This requires balancing binding interactions between native and desired receptors, though it is unclear how balancing binding interactions affects host range and resulting evolutionary trajectories. To provide insights, we surveyed a suite of phage engineering methods to program protein-protein interactions between phage and bacteria and then measured host range expansion and evolutionary trajectories. We engineered T3 and T7, both LPS-targeting phages, to target a proteinaceous nanobody receptor. In addition, we discovered that the capsid plays a role in phage host range and can be a potential target for host range expansion. Together, these studies increase the therapeutic potential for T3 and T7, and more broadly for LPS-targeting phages.