A Whole-Cell Screening Platform for Discovering Cell Adhesion Molecules Enabling Programmable Bacterial Cell-Cell Adhesion

To identify cell adhesion molecules (CAMs) targeting bacterial membrane proteins within a synthetic bacteria-displayed nanobody library, we present a comprehensive whole-cell screening platform. This involves targeted amplicon sequencing to discover nanobodies targeting the natural adhesin, TraN. Furthermore, we employ deep mutational engineering to enhance the binding affinity of these nanobodies toward TraN. Nanobody genes were sequenced after extracting plasmids containing these genes from a bacterial whole-cell display platform, both before and after 1-3 rounds of selection. The selection process aimed to identify nanobodies specifically targeting the surface-exposed domain of TraN from the pSLT plasmid of Salmonella Typhimurium LT2 strain.