Antimicrobial Activity of Snake β-Defensins and Derived Peptides.

Nancy Oguiura,Ana Olívia De Souza,Poliana Garcia Corrêa,Kerly Fernanda Mesquita Pasqualoto,Isabella Lemos Rosmino

doi:10.3390/toxins14010001

Nancy Oguiura, Ana Olívia De Souza + Show 3 more

Open Access

https://doi.org/10.3390/toxins14010001

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Abstract

β-defensins are antimicrobial peptides presenting in vertebrate animals. They participate in innate immunity, but little is known about them in reptiles, including snakes. Although several β-defensin genes were described in Brazilian snakes, their function is still unknown. The peptide sequence from these genes was deduced, and synthetic peptides (with approximately 40 amino acids and derived peptides) were tested against pathogenic bacteria and fungi using microbroth dilution assays. The linear peptides, derived from β-defensins, were designed applying the bioisosterism strategy. The linear β-defensins were more active against Escherichia coli, Micrococcus luteus, Citrobacter freundii, and Staphylococcus aureus. The derived peptides (7–14 mer) showed antibacterial activity against those bacteria and on Klebsiella pneumoniae. Nonetheless, they did not present activity against Candida albicans, Cryptococcus neoformans, Trychophyton rubrum, and Aspergillus fumigatus showing that the cysteine substitution to serine is deleterious to antifungal properties. Tryptophan residue showed to be necessary to improve antibacterial activity. Even though the studied snake β-defensins do not have high antimicrobial activity, they proved to be attractive as template molecules for the development of antibiotics.

Highlights

The sequences of mature peptides were deduced from gene codifying sequences and synthesized, except crotamine purified from venom
They were tested in linear form because the linearization could not affect the antibacterial activity, and the linear form facilitates the development of shorter peptides
The β-defensins were tested against B. jararaca oral flora because it would be of biological and medical interest

Summary

Introduction

With the frightening advent of the global increase of microbial resistance to conventional antibiotics, the search for alternatives has become of utmost importance, and the industry, as well as the regulatory authorities, are realizing the potential of antimicrobial peptides. Bacterial resistance is a global health problem due to the indiscriminate use of antibiotics in humans, as well as in animals and in agricultural production that needs multipronged solutions [3]. To contribute to this campaign, many antimicrobial peptides have been discovered and some are in the clinical development phase [4]. Molecules from innate immunity, such as cathelicidins present in snake venoms, have been reported as potentially active against some bacterial strains [5,6,7,8,9,10], including antibiofilm activity [11,12]

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