title: The PqqD homologous domain of the radical SAM enzyme ThnB is required for thioether bond formation during thurincin H maturation.
abstract: Thurincin H is a 31-residue, ribosomally synthesized bacteriocin originating from the thn operon of Bacillus thuringiensis SF361. It is the only known sactipeptide carrying four thioether bridges between four cysteines and the α-carbons of a serine, an asparagine and two threonine residues. By analysis of the thn operon and use of in vitro studies we now reveal that ThnB is a radical S-adenosylmethionine (SAM) enzyme containing two [4Fe-4S] clusters. Furthermore, we confirm the involvement of ThnB in the formation of the thioether bonds present within the structure of thurincin H. Finally, we show that the PqqD homologous N-terminal domain of ThnB is essential for maturation of the thurincin H precursor peptide, but not for the SAM cleavage activity of ThnB.
authors.affiliation: Department of Chemistry/Biochemistry, LOEWE Center for Synthetic Microbiology, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany.
authors.forename: Beata M
authors.initials: BM
authors.lastname: Wieckowski
authors.affiliation: Department of Chemistry/Biochemistry, LOEWE Center for Synthetic Microbiology, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany.
authors.forename: Julian D
authors.initials: JD
authors.lastname: Hegemann
authors.affiliation: Department of Chemistry/Biochemistry, LOEWE Center for Synthetic Microbiology, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Mielcarek
authors.affiliation: Department of Chemistry/Biochemistry, LOEWE Center for Synthetic Microbiology, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany.
authors.forename: Linda
authors.initials: L
authors.lastname: Boss
authors.affiliation: Department of Chemistry/Biochemistry, LOEWE Center for Synthetic Microbiology, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany.
authors.forename: Olaf
authors.initials: O
authors.lastname: Burghaus
authors.affiliation: Department of Chemistry/Biochemistry, LOEWE Center for Synthetic Microbiology, Philipps-Universität Marburg, Hans-Meerwein-Strasse 4, 35032 Marburg, Germany. Electronic address: marahiel@staff.uni-marburg.de.
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Marahiel
mesh_terms: D000595:Amino Acid Sequence; D001413:Bacillus thuringiensis / Q000378:metabolism; D001430:Bacteriocins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006867:Hydrolases / Q000378:metabolism*; D008969:Molecular Sequence Data; D009876:Operon; D013440:Sulfides / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001430:Bacteriocins; D013440:Sulfides; C568940:thurincin H; D006867:Hydrolases; C019614:adenosylmethionine hydrolase
keywords: Biosynthesis; Natural product; Radical SAM enzyme; Ribosomal peptide; Sactipeptide; [4Fe–4S] cluster