title: Nucleophilic 1,4-additions for natural product discovery.
abstract: Natural products remain an important source of drug candidates, but the difficulties inherent to traditional isolation, coupled with unacceptably high rates of compound rediscovery, limit the pace of natural product detection. Here we describe a reactivity-based screening method to rapidly identify exported bacterial metabolites that contain dehydrated amino acids (i.e., carbonyl- or imine-activated alkenes), a common motif in several classes of natural products. Our strategy entails the use of a commercially available thiol, dithiothreitol, for the covalent labeling of activated alkenes by nucleophilic 1,4-addition. Modification is easily discerned by comparing mass spectra of reacted and unreacted cell surface extracts. When combined with bioinformatic analysis of putative natural product gene clusters, targeted screening and isolation can be performed on a prioritized list of strains. Moreover, known compounds are easily dereplicated, effectively eliminating superfluous isolation and characterization. As a proof of principle, this labeling method was used to identify known natural products belonging to the thiopeptide, lanthipeptide, and linaridin classes. Further, upon screening a panel of only 23 actinomycetes, we discovered and characterized a novel thiopeptide antibiotic, cyclothiazomycin C.
authors.affiliation: Department of Microbiology, ‡Institute for Genomic Biology, and §Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors.forename: Courtney L
authors.initials: CL
authors.lastname: Cox
authors.forename: Jonathan I
authors.initials: JI
authors.lastname: Tietz
authors.forename: Karol
authors.initials: K
authors.lastname: Sokolowski
authors.forename: Joel O
authors.initials: JO
authors.lastname: Melby
authors.forename: James R
authors.initials: JR
authors.lastname: Doroghazi
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Mitchell
mesh_terms: D039903:Actinobacteria / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000596:Amino Acids / Q000737:chemistry; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D001430:Bacteriocins / Q000737:chemistry; D001688:Biological Products / Q000737:chemistry*; D019295:Computational Biology / Q000379:methods; D004229:Dithiothreitol / Q000378:metabolism; D055808:Drug Discovery; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D005021:Ethylamines / Q000737:chemistry; D013058:Mass Spectrometry; D015394:Molecular Structure; D005810:Multigene Family; D010456:Peptides, Cyclic / Q000737:chemistry / Q000494:pharmacology; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013844:Thiazoles / Q000737:chemistry / Q000494:pharmacology; D013883:Thiostrepton / Q000378:metabolism
chemical_list: D000596:Amino Acids; D000900:Anti-Bacterial Agents; D001430:Bacteriocins; D001688:Biological Products; D005021:Ethylamines; D010456:Peptides, Cyclic; D013844:Thiazoles; C000601707:cyclothiazomycin C; C587184:geobacillin I; C027070:N,N-diisopropylethylamine; D013883:Thiostrepton; D004229:Dithiothreitol