Session
Speaker
The Utilization of Proteomics and Gel-Free Peptidomics to Find Novel Plant Antimicrobial Peptides and to Understand the Relative Bacterial Resistance
Octavio Luiz Franco, Simoni Campos Dias, Fabiano Fernandes, Elizabeth Souza Candido, Thais Bergaminn Lima, Simone Maria-Neto, Joćo Suender Moreira, Suzana Meira Ribeiro, Osmar Nascimento Silva
Brasilia
Nowadays, a remarkable increase of human pathogenic microorganisms with enhanced resistance to conventional antibiotics has been observed. In order to control them, several strategies have been adopted such as the use of antimicrobial peptides (AMPs). AMPs are widely expressed in multiple organisms and are evolutionarily related to the innate defense of plants.
These compounds are able directly interact with infectious agents protecting host organism. This report will show the identification and characterization of five plant antimicrobial peptides from flowers, seeds and other plant tissues, demonstrating purification profiles, calculated MICs and structural prediction by molecular modeling and dynamics. Beside of classical biochemical strategy utilized for peptide isolation, gel-free peptidomics was also utilized to explore Brazilian native flowers in order to find a wide number of antimicrobial peptides in a single step.
This strategy, utilizing liquid isoelectric focusing coupled to LC-MS, successfully obtained twenty different peptides with antimicrobial potential. Finally, proteomics was also used to evaluate the bacterial resistance toward antimicrobial peptides. Firstly, Escherichia coli cells with enhanced resistance to magainin were generated. Comparative proteomics by using 2D gels were conduced at resistant and not resistant bacterial sub-proteomes (membranes, cell walls and secretions) showing clear differences in protein maps. MS/MS identification of differential proteins was conduced indicating new molecular targets for a next antibiotics generation. In summary, strategies here presented were used to identify novel antimicrobial drugs and also to preview the future of bacterial resistance.
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