Mutational analysis of mesentericin y105, an anti-Listeria bacteriocin, for determination of impact on bactericidal activity, in vitro secondary structure, and membrane interaction.
Mesentericin Y105 is a 37-residue bacteriocin produced by Leuconostoc mesenteroides Y105 that displays antagonistic activity against gram-positive bacteria such as Enterococcus faecalis and Listeria monocytogenes. It is closely related to leucocin A, an antimicrobial peptide containing beta-sheet and alpha-helical structures. To analyze structure-function relationships and the mode of action of this bacteriocin, we generated a collection of mesentericin derivatives. Mutations were obtained mostly by PCR random mutagenesis, and the peptides were produced by an original system of heterologous expression recently described. Ten derivatives were obtained displaying modifications at eight different positions in the mesentericin Y105 sequence. Purified peptides were incorporated into lysophosphatidylcholine micelles and analyzed by circular dichroism. The alpha-helical contents of these peptides were compared and related to their respective bactericidal activities. Moreover, studies of the intrinsic fluorescence of tryptophan residues naturally occurring at positions 18 and 37 revealed information about insertion of the peptides in micelles. A model for the mode of action of mesentericin Y105 and related bacteriocins is proposed.
Institut de Biologie Moléculaire et d'Ingénierie Génétique, Equipe de Microbiologie Fondamentale et Appliquée, UMR CNRS 6008, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France.
Dany
D
Morisset
Jean-Marc
JM
Berjeaud
Didier
D
Marion
Christian
C
Lacombe
Jacques
J
Frère
D000595:Amino Acid Sequence; D001430:Bacteriocins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D002942:Circular Dichroism; D007934:Leuconostoc / Q000378:metabolism; D008087:Listeria / Q000187:drug effects*; D008089:Listeria monocytogenes / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009154:Mutation; D016415:Sequence Alignment; D013329:Structure-Activity Relationship
D001430:Bacteriocins; C079275:mesentericin Y105 protein, Leuconostoc mesenteroides