Download MendeleyReactivity-Based Screening for Citrulline-Containing Natural Products Reveals a Family of Bacterial Peptidyl Arginine Deiminases.
Harris, L.A., Saint-Vincent, P.M.B., Guo, X., Hudson, G.A., DiCaprio, A.J., Zhu, L., Mitchell, D.A.(2020) ACS Chem Biol 15: 3167-3175
- PubMed: 33249828
- DOI: https://doi.org/10.1021/acschembio.0c00685
- Primary Citation of Related Structures:
7JS6 - PubMed Abstract:
Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a family of natural products defined by a genetically encoded precursor peptide that is processed by associated biosynthetic enzymes to form the mature product. Lasso peptides are a class of RiPP defined by an isopeptide linkage between the N-terminal amine and an internal Asp/Glu residue with the C-terminal sequence threaded through the macrocycle. This unique lariat topology, which typically provides considerable stability toward heat and proteases, has stimulated interest in lasso peptides as potential therapeutics. Post-translational modifications beyond the class-defining, threaded macrolactam have been reported, including one example of Arg deimination to yield citrulline (Cit). Although a Cit-containing lasso peptide (i.e., citrulassin) was serendipitously discovered during a genome-guided campaign, the gene(s) responsible for Arg deimination has remained unknown. Herein, we describe the use of reactivity-based screening to discriminate bacterial strains that produce Arg- versus Cit-bearing citrulassins, yielding 13 new lasso peptide variants. Partial phylogenetic profiling identified a distally encoded peptidyl arginine deiminase (PAD) gene ubiquitous to the Cit-containing variants. Absence of this gene correlated strongly with lasso peptide variants only containing Arg (i.e., des -citrulassin). Heterologous expression of the PAD gene in a des -citrulassin producer resulted in the production of the deiminated analog, confirming PAD involvement in Arg deimination. The PADs were then bioinformatically surveyed to provide a deeper understanding of their taxonomic distribution and genomic contexts and to facilitate future studies that will evaluate any additional biochemical roles for the superfamily.
