title: Characterization of modification enzyme NukM and engineering of a novel thioether bridge in lantibiotic nukacin ISK-1.
abstract: The lantibiotic nukacin ISK-1 is an antimicrobial peptide containing unusual amino acids such as lanthionine and dehydrobutyrine. The nukacin ISK-1 prepeptide (NukA) undergoes posttranslational modifications, such as the dehydration and cyclization reactions required to form the unusual amino acids by the modification enzyme NukM. We have previously constructed a system for the introduction of unusual amino acids into NukA by coexpression of NukM in Escherichia coli. Using this system, we describe the substrate specificity of NukM by the coexpression of a series of NukA mutants. Our results revealed the following characteristics of NukM: (1) its dehydration activity is not coupled to its cyclization activity; (2) its dehydration activity is site-specific; (3) the length of the substrate is important for its dehydration activity. Furthermore, we succeeded in introducing a novel thioether bridge in NukA by replacing an unmodified Ser at position 27 with a Cys residue.
authors.affiliation: Division of Microbial Science and Technology, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Higashi-ku, Fukuoka, Japan.
authors.forename: Kouki
authors.initials: K
authors.lastname: Shioya
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Harada
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Nagao
authors.forename: Jiro
authors.initials: J
authors.lastname: Nakayama
authors.forename: Kenji
authors.initials: K
authors.lastname: Sonomoto
mesh_terms: D000595:Amino Acid Sequence; D001430:Bacteriocins / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism*; D006836:Hydro-Lyases / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D013379:Substrate Specificity
chemical_list: D001430:Bacteriocins; D029968:Escherichia coli Proteins; C421186:nukacin ISK-1; D006836:Hydro-Lyases; C505225:NukM protein, E coli