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Advisor(s)
Abstract(s)
The potential of antimicrobial peptides (AMPs) as an alter native to conventional therapies is well recognized. Insights into
the biological and biophysical properties of AMPs are thus key
to understanding their mode of action. In this study, the mech anisms adopted by two AMPs in disrupting the Gram-negative
Escherichia coli bacterial envelope were explored. BP100 is a
short cecropin A-melittin hybrid peptide known to inhibit the
growth of phytopathogenic Gram-negative bacteria. pepR, on
the other hand, is a novel AMP derived from the dengue virus
capsid protein. Both BP100 and pepR were found to inhibit the
growth of E. coli at micromolar concentrations. Zeta potential
measurements of E. coli incubated with increasing peptide
concentrations allowed for the establishment of a correlation
between the minimal inhibitory concentration (MIC) of each
AMP and membrane surface charge neutralization. While a
neutralization-mediated killing mechanism adopted by either
AMP is not necessarily implied, the hypothesis that surface neu tralization occurs close to MIC values was confirmed. Atomic
force microscopy (AFM) was then employed to visualize the
structural effect of the interaction of each AMP with the E. coli
cell envelope. At their MICs, BP100 and pepR progressively
destroyed the bacterial envelope, with extensive damage already
occurring 2 h after peptide addition to the bacteria. A similar
effect was observed for each AMP in the concentration-depen dent studies. At peptide concentrations below MIC values, only
minor disruptions of the bacterial surface occurred.
Description
Keywords
Antimicrobial peptides Atomic force microscopy Bacteria Dynamic light scattering Membrane structure . Faculdade de Ciências Exatas e da Engenharia
Citation
Alves, C. S., Melo, M. N., Franquelim, H. G., Ferre, R., Planas, M., Feliu, L., ... & Castanho, M. A. (2010). Escherichia coli cell surface perturbation and disruption induced by antimicrobial peptides BP100 and pepR. Journal of Biological Chemistry, 285(36), 27536-27544.
Publisher
Elsevier