SMALL PEPTIDES DERIVED FROM PENETRATIN AS ANTIBACTERIAL AGENTS

PARRAVICINI, OSCAR; S. A. ANDUJAR,; ADRIANA D GARRO; BEATRIZ LIMA; ALEJANDRO TAPIA; GABRIELA FERESIN; R D ENRIZ

San Miguel de Tucuman

Congreso; Congreso de SAB; 2016

Soc Argentina de BIOFISICA

Penetratin is a synthetic small cationic peptide possessing 16 aminoacids which might penetrate cell membrane. Our research group was the first to report the antimicrobial activity of penetratin and some structurally related peptides [1-3]. We report here the antibacterial activity of new peptides structurally related to penetratin and an exhaustive conformational analysis as physicochemical properties of these peptides may play a key role in producing their antibacterial effects.Minimal inhibitory concentration values were determined using the broth microdilution method according to the protocols of the CLSI. Conformational analysis was performed using the GROMACS programs package and circular dichroism spectroscopic measurements. Two different media (water and trifluoroethanol/water) were employed.In vitro antibacterial effects and conformational study of 13 small-size peptides were accomplished. These were found to be very active antibacterial compounds, considering their small molecular size. Theoretical simulations showed that peptide helical structure is destroyed using the matrix-mimetic environment, resulting in a mixture of β-turn, bend and coil. In contrast, residues adopted a helix-like conformation using the membrane-mimetic environment, being α-helix the predominant form. Initial and final amino acids appear to have a random coil structure. Analysis based on circular dichroism measurements were in agreement with theoretical results.The antibacterial activity within the series is mainly dominated by aminoacid composition adopting a definite spatial ordering. Some of this compounds are the most active small peptides reported until now and constitute interesting structures for the design of new small-size peptides possessing antibacterial activity.