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The PqqD homologous domain of the radical SAM enzyme ThnB is required for thioether bond formation during thurincin H maturation
Author(s) -
Wieckowski Beata M.,
Hegemann Julian D.,
Mielcarek Andreas,
Boss Linda,
Burghaus Olaf,
Marahiel Mohamed A.
Publication year - 2015
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2015.05.032
Subject(s) - thioether , operon , chemistry , asparagine , residue (chemistry) , stereochemistry , serine , peptide bond , threonine , biochemistry , enzyme , gene , escherichia coli
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.