Next-Generation Antimicrobial Discovery through Bacterial Self-Screening of Surface-Displayed Peptide Libraries [HiSeq]

Peptides have great potential to combat antibiotic resistance. While many platforms can screen peptides for their ability to bind to target cells, there are virtually no platforms that directly assess the functionality of peptides. This limitation is exacerbated when identifying antimicrobial peptides, since the phenotype, death, selects against itself, and has caused a scientific bottleneck confining research to only a few naturally occurring classes of antimicrobial peptides. We have used this seeming dissonance to develop Surface Localized Antimicrobial displaY (SLAY); a platform that allows screening of unlimited numbers of peptides of any length, composition, and structure in a single tube for antimicrobial activity. Using SLAY, we screened ~800,000 random peptide sequences for antimicrobial function and identified thousands of active sequences doubling the number of known antimicrobial sequences. SLAY hits present with different potential mechanisms of peptide action and access to areas of antimicrobial physicochemical space beyond what nature has evolved. An 800,000 random peptide library was genetically encoded into our surface display system.We used high-throughput sequencing (Hi-seq) to identify surface expressed peptides with antimicrobial activity against E. coli. Samples include a non-induced and an induced (4- hours post-induction) in duplicate. Please note that the Miseq run was a much smaller set of peptides than the Hiseq run. Also the miseq run had samplings at 0, 2, 3 and 4 hours rather than just 0 and 4 hours in the Hiseq. Downstream analysis was the same.