Ga. Dykes et al., STRUCTURAL VARIATIONS IN NISIN ASSOCIATED WITH DIFFERENT MEMBRANE MIMICKING AND PH ENVIRONMENTS, Biochemical and biophysical research communications (Print), 247(3), 1998, pp. 723-727
Nisin is a membrane active antimicrobial peptide containing unusual de
hydrated amino acid residues. The secondary structure of nisin in aque
ous solution, membrane mimicking solvents and at various pH values was
investigated using circular dichroism. In aqueous solution nisin is l
argely randomly coiled. In liposomes and at pH 6 and above, however, t
he 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 cha
nge in structure was speculated to result in an increasing unavailabil
ity of the site for initial reaction of peptide and membrane at higher
pH. (C) 1998 Academic Press.