A molecular view by FITR spectroscopy of the relationship between lactocin 705 and membranes:speculations on antimicrobial mechanism.

PATRICIA CASTELLANO; GRACIELA VIGNOLO; RICARDO FARÍAS; JOSÉ LUIS ARRONDO; ROSANA CHEHÍN

APPLIED AND ENVIRONMENTAL MICROBIOLOGY

American Society for Microbiology

Lugar: Washington; Año: 2007 vol. 73 p. 415 - 420

0099-2240

lactocin 705 is a bacteriocin whose activity deoends upon the complementation of two peptides, termed lac705a and lac705b. neither lac705a nor lac705b displayed bacteriocin activity by itself when the growth of sensitive cells was monitored. To obtain molecular insights inyo the lactoci 705 mechanism of action, Fourier transform infrared spectroscopy was used to invetigate the interactions of each peptide (Lac705a and lac705b) with dipalmitoylphosphatydilcholine liposomal membranes. Both peptides show the ability to interact with the zwitterionic membrane but at different bilayer levels. While lac705a interacts with the interfacial region inducing dehydratation, lac705b peptide interacts with only the hydrophobic core. This paper presents the first experimenat evidence that supports the hypothesis that lac705 a and lac705b peptides could form a transmembrane oligomer. From the obtained results, a mechanism of action of lactocin 705 on membrane systems os proposed. The component lac705a could induce the dehydration of the bilayer interfacial region, and the lac705b peptide could insert in the hydrophobic region of the membrane where the peptide has adequate conditions to achieve the oligomerization.