title: In Vitro Biosynthesis of the Core Scaffold of the Thiopeptide Thiomuracin.
abstract: Thiopeptides are potent antibiotics that inhibit protein synthesis. They are made by a remarkable post-translational modification process that transforms a linear peptide into a polycyclic structure. We present here the in vitro biosynthesis of the core scaffold of thiomuracin catalyzed by six proteins. We show that cyclodehydration precedes dehydration, and that dehydration is catalyzed by two proteins in a tRNA(Glu)-dependent manner. The enzyme that generates the pyridine core from two dehydroalanines ejects the leader peptide as a C-terminal carboxamide. Mutagenesis studies of the enzyme TbtD identified important residues for a formal [4+2] cycloaddition process. The core structure of thiomuracin exhibits similar antimicrobial activity to other known congeners, illustrating that in vitro biosynthesis is a viable route to potent antibiotics that can be explored for the rapid and renewable generation of analogues.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Graham A
authors.initials: GA
authors.lastname: Hudson
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Zhengan
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Jonathan I
authors.initials: JI
authors.lastname: Tietz
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.|Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign , 1206 West Gregory Drive, Urbana, Illinois 61801, United States.
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Mitchell
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States.|Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign , 1206 West Gregory Drive, Urbana, Illinois 61801, United States.
authors.forename: Wilfred A
authors.initials: WA
authors.lastname: van der Donk
mesh_terms: D066298:In Vitro Techniques; D010455:Peptides / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*
chemical_list: D010455:Peptides; D013438:Sulfhydryl Compounds