Heterologous production of antimicrobial peptides in yeast allows for massive assessment of the activity of DNA-encoded antimicrobials <i>in situ</i>

Antibiotic resistance threatens global healthcare. In clinical practice, conventional antibiotics are becoming gradually less effective. Moreover, the introduction of new antimicrobial agents into clinical practice leads to the emergence of resistant pathogenic strains within just a few years. Hence, the development of platforms for massive creation and screening of new antimicrobial agents is of particular importance. Massive parallel screening will greatly reduce the time required to identify the most promising drug candidates. Meanwhile, DNA-encoded antimicrobial agents offer unique opportunities for the high-throughput development of new antibiotics. Here, the yeast <i>Pichia pastoris</i> was engineered to produce a panel of antimicrobial peptides (AMPs), followed by high-throughput screening of AMP producers that inhibit bacterial growth <i>in situ</i>. Yeast clones producing thanatin and protegrin-1 exhibited the highest level of antimicrobial activity among the panel of AMPs under investigation. The production level of recombinant thanatin was significantly higher than that of protegrin-1, which correlates with its low toxicity. The designed technique of massive assessment of the activity of DNA-encoded antimicrobial agents enables the identification of drug candidates with an increased therapeutic index. Further development of methods for a rational design of artificial diversity in AMPs, followed by deep functional profiling of antimicrobial activity, will yield new AMPs with improved therapeutic characteristics.