title: Molecular view by fourier transform infrared spectroscopy of the relationship between lactocin 705 and membranes: speculations on antimicrobial mechanism.
abstract: Lactocin 705 is a bacteriocin whose activity depends upon the complementation of two peptides, termed Lac705alpha and Lac705beta. Neither Lac705alpha nor Lac705beta displayed bacteriocin activity by itself when the growth of sensitive cells was monitored. To obtain molecular insights into the lactocin 705 mechanism of action, Fourier transform infrared spectroscopy was used to investigate the interactions of each peptide (Lac705alpha and Lac705beta) with dipalmitoylphosphatidylcholine liposomal membranes. Both peptides show the ability to interact with the zwitterionic membrane but at different bilayer levels. While Lac705alpha interacts with the interfacial region inducing dehydration, Lac705beta peptide interacts with only the hydrophobic core. This paper presents the first experimental evidence that supports the hypothesis that Lac705alpha and Lac705beta peptides could form a transmembrane oligomer. From the obtained results, a mechanism of action of lactocin 705 on membrane systems is proposed. The component Lac705alpha could induce the dehydration of the bilayer interfacial region, and the Lac705beta peptide could insert in the hydrophobic region of the membrane where the peptide has adequate conditions to achieve the oligomerization.
authors.affiliation: Centro de Referencia para Lactobacilos (CERELA/CONICET), Chacabuco 145 Tucumán, Argentina.
authors.forename: Patricia
authors.initials: P
authors.lastname: Castellano
authors.forename: Graciela
authors.initials: G
authors.lastname: Vignolo
authors.forename: Ricardo Norberto
authors.initials: RN
authors.lastname: Farías
authors.forename: José Luis
authors.initials: JL
authors.lastname: Arrondo
authors.forename: Rosana
authors.initials: R
authors.lastname: Chehín
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D000595:Amino Acid Sequence; D001430:Bacteriocins / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects*; D008051:Lipid Bilayers; D008081:Liposomes; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013696:Temperature
chemical_list: D001430:Bacteriocins; D008051:Lipid Bilayers; D008081:Liposomes; D010455:Peptides; D015060:1,2-Dipalmitoylphosphatidylcholine; C035728:lactocin