title: Engineering dehydrated amino acid residues in the antimicrobial peptide nisin.
abstract: The small antimicrobial peptide nisin, produced by Lactococcus lactis, contains the uncommon amino acid residues dehydroalanine and dehydrobutyrine and five thio ether bridges. Since these structures are posttranslationally formed from Ser, Thr, and Cys residues, it is feasible to study their role in nisin function and biosynthesis by protein engineering. Here we report the development of an expression system for mutated nisin Z (nisZ) genes, using nisin A producing L. lactis as a host. Replacement by site-directed mutagenesis of the Ser-5 codon in nisZ by a Thr codon, led to a mutant with a dehydrobutyrine instead of a dehydroalanine residue at position 5, as shown by NMR. Its antimicrobial activity was 2-10-fold lower relative to wild-type nisin Z, depending on the indicator strain used. In another mutagenesis study a double mutation was introduced in the nisZ gene by replacing the codons for Met-17 and Gly-18 by codons for Gln and Thr, respectively, as in the third lanthionine ring of the related antimicrobial peptide subtilin from Bacillus subtilis. This resulted in the simultaneous production of two mutant species, one containing a Thr residue and the other containing a dehydrobutyrine residue at position 18, both having different bacteriocidal properties.
authors.affiliation: Department of Biophysical Chemistry, Netherlands Institute for Dairy Research (NIZO), Ede.
authors.forename: O P
authors.initials: OP
authors.lastname: Kuipers
authors.forename: H S
authors.initials: HS
authors.lastname: Rollema
authors.forename: W M
authors.initials: WM
authors.lastname: Yap
authors.forename: H J
authors.initials: HJ
authors.lastname: Boot
authors.forename: R J
authors.initials: RJ
authors.lastname: Siezen
authors.forename: W M
authors.initials: WM
authors.lastname: de Vos
mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development; D001483:Base Sequence; D003001:Cloning, Molecular / Q000379:methods; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004926:Escherichia coli / Q000235:genetics; D013294:Lactococcus lactis / Q000235:genetics*; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009561:Nisin / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology; D009838:Oligodeoxyribonucleotides; D016133:Polymerase Chain Reaction / Q000379:methods; D011487:Protein Conformation; D015202:Protein Engineering / Q000379:methods*; D011994:Recombinant Proteins / Q000737:chemistry / Q000494:pharmacology; D015183:Restriction Mapping; D013329:Structure-Activity Relationship
chemical_list: D004269:DNA, Bacterial; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D009561:Nisin