TY - JOUR TI - Mapping the functional landscape of the receptor binding domain of T7 bacteriophage by deep mutational scanning AU - Huss, Phil AU - Meger, Anthony AU - Leander, Megan AU - Nishikawa, Kyle AU - Raman, Srivatsan A2 - Storz, Gisela A2 - Turnbaugh, Peter A2 - Debarbieux, Laurent A2 - Duerkop, Breck A A2 - Fraser, James S VL - 10 PY - 2021 DA - 2021/03/09 SP - e63775 C1 - eLife 2021;10:e63775 DO - 10.7554/eLife.63775 UR - https://doi.org/10.7554/eLife.63775 AB - The interaction between a bacteriophage and its host is mediated by the phage's receptor binding protein (RBP). Despite its fundamental role in governing phage activity and host range, molecular rules of RBP function remain a mystery. Here, we systematically dissect the functional role of every residue in the tip domain of T7 phage RBP (1660 variants) by developing a high-throughput, locus-specific, phage engineering method. This rich dataset allowed us to cross compare functional profiles across hosts to precisely identify regions of functional importance, many of which were previously unknown. Substitution patterns showed host-specific differences in position and physicochemical properties of mutations, revealing molecular adaptation to individual hosts. We discovered gain-of-function variants against resistant hosts and host-constricting variants that eliminated certain hosts. To demonstrate therapeutic utility, we engineered highly active T7 variants against a urinary tract pathogen. Our approach presents a generalized framework for characterizing sequence–function relationships in many phage–bacterial systems. KW - Bacteriophage KW - phage KW - virus KW - deep mutational scanning KW - synthetic biology KW - tail fiber JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -