Permeation studies and control release of antimicrobial peptides structurally derived from CcdB toxin

• Grant number: 12/23576-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2013
• End date: June 30, 2014
• Field of knowledge: Physical Sciences and Mathematics - Chemistry
• Principal Investigator: Saulo Santesso Garrido
• Grantee: Carolina Reis Zambom
• Host Institution: Instituto de Química (IQ). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

The use of synthetic peptides for the development of new drugs is a promising strategy in the fields of biotechnology. Peptides derived from intracellular bacterial toxins produced by systems of the post-segregational killer (PKS) such as CcdB is an example of this strategy. However, drugs with peptide structures derived from bacterial toxins present serious problems in therapeutic application because of their low solubility and low permeability in bacterial membranes. The aim of this study is the development and enhancement of nanostructured systems (liposomes) that enable the immobilization of peptide analogs of CcdB toxin and its consequent bacterial translocation into the cytosol, allowing them to reach their cellular targets, which are the bacterial enzymes DNA gyrase and topoisomerase IV. LUV liposomes type ("large unilamellar vesicles") of 100 nm diameter, are prepared by an extrusion-evaporation technique by varying the chemical composition of their formulations. Thus, it is intended to evaluate the encapsulation efficiency of the peptides through techniques of high-performance liquid chromatography (HPLC) and UV-Vis spectroscopy and fluorescence. After testing encapsulation efficiency, liposomes containing peptide analogs of CcdB toxin encapsulated will undergo growth inhibition assay in liquid medium for different bacterial species. Preliminary tests showed the free peptides in solution have no ability to inhibit bacterial growth. These results demonstrate that the use of nanostructured systems to promote the entry of these synthetic peptides in bacterial cytosol is very important to enable the application of those biomolecules in therapeutic studies. Thus these peptides may be used as antibiotics promising systems when associated with efficient transport and controlled systems.(AU)