Understanding the mechanism of action of peptide (p-BthTX-I)(2) derived from C-terminal region of phospholipase A2 (PLA(2))-like bothropstoxin-I on Gram-positive and Gram-negative bacteria

Author(s)

Santos-Filho, Norival Alves ; de Freitas, Laura Marise ; Dos Santos, Claudia Tavares ; Piccoli, Julia Pinto ; Fontana, Carla Raquel ; Fusco-Almeida, Ana Marisa ; Cilli, Eduardo Maffud

• Document type: Journal article
• Source: Toxicon; v. 196, p. 12-pg., 2021-04-08.

Abstract

Based on the antimicrobial activity of bothropstoxin-I (BthTX-I) and on the premise that a C-terminal peptide of Lys49 myotoxin can reproduce the antimicrobial activity of the parent protein, we aimed to study the mechanism of action of a peptide derived from the C-terminal region of the myotoxin BthTX-I [(p-BthTX-I)(2), sequence: KKYRYHLKPFCKK, disulfide-linked dimer] against Gram-positive and Gram-negative bacteria. Fluorescence quenching technique showed that the carboxyfluorescein labeled-peptide [CF-(p-BthTX-I)(2)] when incubated with E. coli displayed a superior penetration activity than when incubated with S. aureus. Cell death induced by the peptide (p-BthTX-I)(2) showed a loss of membrane integrity in E. coli and S. aureus; however, the mechanisms of cell death were different, characterized by the presence of necrosis-like and apoptosis-like deaths, respectively. Scanning electron microscopy studies in E. coli and S. aureus showed morphological changes in the cells, with superficial deformities, appearance of wrinkles and bubbles, and formation of vesicles. Our results demonstrate that the mechanism of action of the peptide (p-BthTX-I)(2) is different in Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria. Knowledge of the mechanism of action of these peptides is important, since they are promising prototypes for new antimicrobial drugs. (AU)

• FAPESP's process: 14/24581-5 - Evaluation of the role of photodynamic therapy combined with antimicrobial peptides against bacterial resistance
• Grantee: Laura Marise de Freitas
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/07600-3 - CIBFar - Center for Innovation in Biodiversity and Drug Discovery
• Grantee: Glaucius Oliva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 14/05538-1 - Synthesis, characterization, study of action mechanism and analysis of different release methods of pBthTX-I, in its monomeric and dimeric forms
• Grantee: Norival Alves Santos Filho
• Support Opportunities: Scholarships in Brazil - Post-Doctoral