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| Author(s): |
José Carlos Bozelli Junior
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) |
| Defense date: | 2015-11-24 |
| Examining board members: |
Shirley Schreier;
Ana Paula Valente Lacerda de Almeida;
Iolanda Midea Cuccovia;
Karin do Amaral Riske;
Roberto Kopke Salinas
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| Advisor: | Shirley Schreier |
| Abstract | |
Tritrpticin (TRP3) is a 13-residue antimicrobial peptide that contains three sequential Ws. With the aim of contributing to the understanding of its mechanism of action, functional and conformational studies were performed with TRP3 and two of its analogues where one (WLW) or two (LWL) of the W were replaced by L. The peptides were equally active against both Gram positive and Gram negative bacteria. Higher concentrations were required for hemolytic activity which varied in the order: TRP3>WLW>LWL. The peptides permeabilized membranes model membranes mimicking E. coli\'s lipid composition or containing different negatively charged phospholipids. CD spectra suggested the peptides acquired different conformations upon binding to bilayers or micelles. Fluorescence studies showed that membrane binding decreases in the order: TRP3>WLW>LWL and that the peptides are located close to the water-membrane interface. EPR spectra of lipid spin labels indicated that peptide binding alter lipid organization, increasing molecular packing (AU) | |