title: Structural variations in nisin associated with different membrane mimicking and pH environments.
abstract: Nisin is a membrane active antimicrobial peptide containing unusual dehydrated amino acid residues. The secondary structure of nisin in aqueous solution, membrane mimicking solvents and at various pH values was investigated using circular dichroism. In aqueous solution nisin is largely randomly coiled. In liposomes and at pH 6 and above, however, the presence of a maximum at 195 nm and a minimum at 190 nm was notable and indicative of beta-turn formation in these environments. This change in structure was speculated to result in an increasing unavailability of the site for initial reaction of peptide and membrane at higher pH.
authors.affiliation: Department of Genetics, University of Natal, Scottsville, South Africa. dykesg@gene.unp.ac.za
authors.forename: G A
authors.initials: GA
authors.lastname: Dykes
authors.forename: R E
authors.initials: RE
authors.lastname: Hancock
authors.forename: J W
authors.initials: JW
authors.lastname: Hastings
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry; D002462:Cell Membrane / Q000187:drug effects; D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D008081:Liposomes / Q000378:metabolism; D008968:Molecular Conformation; D009561:Nisin / Q000737:chemistry*; D017433:Protein Structure, Secondary; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D008081:Liposomes; D009561:Nisin; D012967:Sodium Dodecyl Sulfate