title: Targeting Reactive Carbonyls for Identifying Natural Products and Their Biosynthetic Origins.
abstract: Natural products (NPs) serve important roles as drug candidates and as tools for chemical biology. However, traditional NP discovery, largely based on bioassay-guided approaches, is biased toward abundant compounds and rediscovery rates are high. Orthogonal methods to facilitate discovery of new NPs are thus needed, and herein we describe an isotope tag-based expansion of reactivity-based NP screening to address these shortcomings. Reactivity-based screening is a directed discovery approach in which a specific reactive handle on the NP is targeted by a chemoselective probe to enable its detection by mass spectrometry. In this study, we have developed an aminooxy-containing probe to guide the discovery of aldehyde- and ketone-containing NPs. To facilitate the detection of labeling events, the probe was dibrominated, imparting a unique isotopic signature to distinguish labeled metabolites from spectral noise. As a proof of concept, the probe was then utilized to screen a collection of bacterial extracts, leading to the identification of a new analogue of antipain, deimino-antipain. The bacterial producer of deimino-antipain was sequenced and the responsible biosynthetic gene cluster was identified by bioinformatic analysis and heterologous expression. These data reveal the previously undetermined genetic basis for a well-known family of aldehyde-containing, peptidic protease inhibitors, including antipain, chymostatin, leupeptin, elastatinal, and microbial alkaline protease inhibitor, which have been widely used for over 40 years.
authors: Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors: Tucker
authors: T
authors: Maxson
authors: Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors: Jonathan I
authors: JI
authors: Tietz
authors: Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors: Graham A
authors: GA
authors: Hudson
authors: Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors: Xiao Rui
authors: XR
authors: Guo
authors: Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors: Hua-Chia
authors: HC
authors: Tai
authors: Department of Chemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.|Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.|Department of Microbiology, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
authors: Douglas A
authors: DA
authors: Mitchell
mesh_terms: D000447:Aldehydes / Q000737:chemistry* / Q000378:metabolism; D001688:Biological Products / Q000032:analysis* / Q000378:metabolism*; D019295:Computational Biology; D007659:Ketones / Q000737:chemistry* / Q000378:metabolism; D015394:Molecular Structure; D013302:Streptomyces / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D000447:Aldehydes; D001688:Biological Products; D007659:Ketones