title: Biochemical and Spectroscopic Characterization of a Radical S-Adenosyl-L-methionine Enzyme Involved in the Formation of a Peptide Thioether Cross-Link.
abstract: Peptide-derived natural products are a class of metabolites that afford the producing organism a selective advantage over other organisms in their biological niche. While the polypeptide antibiotics produced by the nonribosomal polypeptide synthetases (NRPS) are the most widely recognized, the ribosomally synthesized and post-translationally modified peptides (RiPPs) are an emerging group of natural products with diverse structures and biological functions. Both the NRPS derived peptides and the RiPPs undergo extensive post-translational modifications to produce structural diversity. Here we report the first characterization of the six cysteines in forty-five (SCIFF) [Haft, D. H. and Basu M. K. (2011) J. Bacteriol. 193, 2745-2755] peptide maturase Tte1186, which is a member of the radical S-adenosyl-l-methionine (SAM) superfamily. Tte1186 catalyzes the formation of a thioether cross-link in the peptide Tte1186a encoded by an orf located upstream of the maturase, under reducing conditions in the presence of SAM. Tte1186 contains three [4Fe-4S] clusters that are indispensable for thioether cross-link formation; however, only one cluster catalyzes the reductive cleavage of SAM. Mechanistic imperatives for the reaction catalyzed by the thioether forming radical SAM maturases will be discussed.
authors.affiliation: Chemistry Department, University of Utah , Salt Lake City, Utah 84112, United States.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Bruender
authors.affiliation: Department of Chemistry, University of California , Davis, California 95616, United States.
authors.forename: Jarett
authors.initials: J
authors.lastname: Wilcoxen
authors.affiliation: Department of Chemistry, University of California , Davis, California 95616, United States.
authors.forename: R David
authors.initials: RD
authors.lastname: Britt
authors.affiliation: Chemistry Department, University of Utah , Salt Lake City, Utah 84112, United States.
authors.forename: Vahe
authors.initials: V
authors.lastname: Bandarian
mesh_terms: D020816:Amino Acid Motifs; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D055162:Biocatalysis; D019295:Computational Biology; D003545:Cysteine / Q000378:metabolism*; D003553:Cystine / Q000378:metabolism*; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010084:Oxidation-Reduction; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000378:metabolism*; D013379:Substrate Specificity; D046968:Thermoanaerobacter / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D003553:Cystine; D012436:S-Adenosylmethionine; D050862:Oxidoreductases Acting on Sulfur Group Donors; D003545:Cysteine