Raman spectroscopy study of the effect of Nisin in unilamellar vesicles of DLPG

JUÁREZ A. CAROLINA; ALVAREZ ROSA MARÍA SUSANA; SOSA MORALES MARCELO C.; BORSARELLI CLAUDIO D.

Tucuman

Congreso; III Latin American Federation of Biophysical Societies (LAFeBS) IX IberoAmerican Congress of Biophysics XLV Reunion Anual SAB 2016; 2016

Sociedad Argentina de Biofísica

Nisin is a cationic peptide with bactericidal activity, produced by different Lactococcus lactis strains. It belongs to a class of antimicrobial polypeptides which is known as Lantibiotics. Nisin contains unusual amino acids, which are formed in posttranslational processes, such as lanthionine (DAla-S-Ala,), -methyllanthionine (DAbu-S-Ala), dehydroalanine (Dha) and dehydrobutyrine (Dhb). (1)Our group is interested in determining the molecular bases of the bacterial activity of Nisin by using spectroscopic techniques such as fluorescence, Raman and FTIR. Previously, by fluorescence studies, we determined the minimum amount of the peptide necessary to produce a significant change in the membrane (2). Now, we are presenting Raman spectroscopy studies related to the structural modifications induced by the peptide incorporation in critical concentrations to unilamellar vesicles (LUV) of dilauroylphosphatidylglycerol (DLPG). The evaluation and interpretation of the intensity ratios of C-H and C-C stretching bands belonging to the lipid hydrocarbon chains, allowed concluding that the incorporated peptide produces an increase in the rigidity of the membrane, in accordance with our results obtained by fluorescence studies.Referencias (1) Frank J. M. Van de Ven, Henno W. Van den Hooven, Ruud N. H. Konings and Cornelis W. Hilbers. Eur. J. Biochem. 202,1181 -1188 (1991).(2) Manuscript in preparation.