Computer-Aided Design of Mastoparan-like Peptides Enables the Generation of Nontoxic Variants with Extended Antibacterial Properties

Abstract

Diverse peptides have been evaluated for their activity against pathogenic microorganisms. Here, five mastoparan variants were designed based on mastoparan-L, among which two (R1 and R4) were selected for in-depth analysis. Mastoparan-L (parent/control), R1, and R4 inhibited susceptible/resistant bacteria at concentrations ranging from 2 to 32 μM, whereas only R1 and R4 eradicated Pseudomonas aeruginosa biofilms at 16 μM. Moreover, the toxic effects of mastoparan-L toward mammalian cells were drastically reduced in both variants. In skin infections, R1 at 64 μM was the most effective variant, reducing P. aeruginosa bacterial counts 1000 times on day 4 post-infection. Structurally, all of the peptides showed varying levels of helicity and structural stability in aqueous and membrane-like conditions, which may affect the different bioactivities observed here. By computationally modifying the physicochemical properties of R1 and R4, we reduced the cytotoxicity and optimized the therapeutic potential of these mastoparan-like peptides both in vitro and in vivo.

Computer-Aided Design of Antimicrobial Peptides: Are We Generating Effective Drug Candidates?

“…As a result, a short central α-helical segment with flexible termini was reported and correlated with the antibacterial properties observed for this peptide (Cardoso et al, 2018a). In recent work with mastoparan peptides, mastoparan-L was used as a template sequence for the generation of mastoparan-R1 and R4 (Oshiro et al, 2019). When evaluated structurally, NMR and temperature coefficient experiments revealed that the levels of structural stability of the peptides follow the order: mastoparan-L > R4 > R1.…”

“…Cytotoxicity remains a fundamental feature in peptide design . Bearing this in mind, Oshiro et al (2019) recently used a peptide sequence (mastoparan-L) isolated from the wasp venom Vespula lewisii (Hirai et al, 1979) as input for the Joker algorithm aimed at reducing the hemolytic and cytotoxic effects of this peptide, as well as improving/extending its antibacterial properties ( Table 2). In that work, five analog sequences were obtained by inserting the α-helical pattern (KK[ILV] [AL]x[RKD] [ILV]xxKI).…”

“…However, we cannot discard the increasing numbers of reports that highlight AMP flexibility as a promising scaffold for multifunctional properties in the context of bacterial and biofilm infections (Pukala et al, 2004;Cardoso et al, 2018a). For instance, AMPs designed by automated antimicrobial pattern insertion, including the above-mentioned EcDBS1R5 and mastoparan-R1/R4, have shown that flexible ( Table 2), helical structures may trigger enhanced antibacterial, antibiofilm, and antiinfective properties (Cardoso et al, 2018a;Oshiro et al, 2019). EcDBS1R5 secondary structure was investigated in different mimetic conditions and its tridimensional structure determined in 30% TFE.…”

“…When evaluated structurally, NMR and temperature coefficient experiments revealed that the levels of structural stability of the peptides follow the order: mastoparan-L > R4 > R1. Interestingly, the most flexible peptide, mastoparan-R1, presented not only antibacterial and antibiofilm activities but was also the most active peptide in vivo (Oshiro et al, 2019).…”

“…Finally, AMPs are known to have diverse modes of action depending on the bacterial targets they interact with and, therefore, are promising candidates for multi-target antibacterial treatments. Although these characteristics appear as promising features for drug development, some disadvantages have been pinpointed for AMP-based therapies, including chemical and physical instability (Zhao et al, 2016), proteolytic degradation (Pachon-Ibanez et al, 2017), short half-life and rapid elimination (Lombardi et al, 2015), slow tissue penetration (Koczulla et al, 2003), toxicity toward healthy human cells, and cell specificity (Oshiro et al, 2019). Based on that, an increasing number of computational strategies are underway, aiming at overcoming these obstacles by optimizing AMP sequences.…”