IDENTIFICAÇÃO DE PEPTÍDEOS COM ATIVIDADE ANTIMICROBIANA UTILIZANDO A BIOINFORMÁTICA

Abstract

Most Antimicrobial Peptides (AMPs) are molecules with a broad spectrum of activities included the treatment of microorganism infections. The computational design of AMPs is an instrument that facilitates the search for new and efficient peptides, facing the new challenges of antimicrobial resistance. The present study investigated the antimicrobial and anti-biofilm activity of the KWI18, a new synthetic peptide against microorganisms which have a high incidence in hospital-acquired infections. The computational design was used to obtain the KWI18 peptide, the analysis of its secondary conformational structure was performed using the circular dichroism spectrum. This peptide was tested against Gram-positive and Gram-negative bacteria, yeasts, as well as against Pseudomonas aeruginosa and Candida parapsilosis biofilm. Time-kill and synergism assays with other antimicrobials were performed, as well as assays of sorbitol, ergosterol and assays of lipid peroxidation and oxidation of proteins seeking to evaluate the mechanism of action. The KWI18 peptide was later tested for its preliminary toxicity in sheep erythrocytes, as well as in an in vivo model of Galleria mellonella. KWI18 has been shown to have a well-defined α-helix structure in contact with TFE and SDS. It showed antimicrobial activity, with minimal inhibitory concentrations (MICs) ranging from 0.5 to 10 µM. Treatment with KWI18 at 10 x MIC significantly reduced biofilm formation and the viability of P. aeruginosa and C. parapsilosis strains. In the time-kill assay, the peptide inhibited the growth of P. aeruginosa in 4h and in 6h of C. parapsilosis at a concentration of 10 x MIC, showing action on fungal membrane interacting with ergosterol, also causing oxidative damage to the strains and their biofilms. Furthermore, it demonstrated low toxicity in sheep erythrocytes at anti-biofilm concentrations, as well as having no systemic toxicity in vivo, demonstrated in G. mellonella. Thus, KWI18 proved to be effective in the proposed anti-biofilm activity, opening opportunities for the development of new antimicrobials. These results present a new molecule with potential antimicrobial and antibiofilm activity.

Keywords: peptide antimicrobial; anti-biofilm; computacional design.