Discovery, Characterization, and Bioactivity of the Achromonodins: Lasso Peptides Encoded by .

Through genome mining efforts, two lasso peptide biosynthetic gene clusters (BGCs) within two different species of , a genus that contains pathogenic organisms that can infect patients with cystic fibrosis, were discovered. Using gene-refactored BGCs in , these lasso peptides, which were named achromonodin-1 and achromonodin-2, were heterologously expressed. Achromonodin-1 is naturally encoded by certain isolates from the sputum of patients with cystic fibrosis. The NMR structure of achromonodin-1 was determined, demonstrating that it is a threaded lasso peptide with a large loop and short tail structure, reminiscent of previously characterized lasso peptides that inhibit RNA polymerase (RNAP). Achromonodin-1 inhibits RNAP and has potent, focused activity toward , another isolate from the sputum of a cystic fibrosis patient. These efforts expand the repertoire of antimicrobial lasso peptides and provide insights into how isolates from certain ecological niches interact with each other.