Rational Design of Short Peptide Variants by Using Kunitzin-RE, an Amphibian-Derived Bioactivity Peptide, for Acquired Potent Broad-Spectrum Antimicrobial and Improved Therapeutic Potential of Commensalism Coinfection of Pathogens

Abstract

Commensalism coinfection of pathogens has seriously jeopardized human health. Currently, Kunitzin-RE, as an amphibian-derived bioactivity peptide, is regarded as a potential antimicrobial candidate. However, its antimicrobial properties were unsatisfactory. In this study, a set of shortened variants of Kunitzin-RE was developed by the interception of a peptide fragment and single-site mutation to investigate the effect of chain length, positive charge, hydrophobicity, amphipathicity, and secondary structure on antimicrobial properties. Among them, W8 (AARIILRWRFR) significantly broadened the antimicrobial spectrum and showed the highest antimicrobial activity (GMall = 2.48 μM) against all the fungi and bacteria tested. Additionally, W8 showed high cell selectivity and salt tolerance in vitro, whereas it showed high effectiveness against mice keratitis cause by infection by C. albicans 2.2086. Additionally, it also had obviously lipopolysaccharide-binding ability and a potent membrane-disruptive mechanism. Overall, these findings contributed to the design of short antimicrobial peptides and to combat the serious threat of commensalism coinfection of pathogens.

Hybrid Antimicrobial Peptide Targeting Staphylococcus aureus and Displaying Anti-infective Activity in a Murine Model

“…The addition of disulfide bonds to the targeting domain enhanced the antimicrobial selectivity against S. aureus , and the modified peptide S2 exhibited specific anti- S. aureus potency, suggesting that disulfide bonds play an important role in the targeting activity against S. aureus ( Leeuw et al, 2007 ). Although S6 showed similar antimicrobial activity as S7, S1 exhibited broad-spectrum antimicrobial activity due to the high number of positive charges, resulting in a high accumulation on anionic bacterial membranes ( Yang et al, 2019 ). S3 and S8 showed no antimicrobial activity due to the decrease in hydrophobicity, resulting in a reduction in the membrane destruction capacity ( Schmidtchen et al, 2014 ).…”

“…Thus, we designed a series of killing domains against S. aureus for the following reasons: (1) Tryptophan (W) has the unique ability to interact with membranes and facilitate peptide anchoring to bacterial surfaces, and the π configuration of the WWW motif of the short tryptophan-rich peptide is critical for the targeting killing of MRSA (Zarena et al, 2017); (2) Hydrophobicity is strongly correlated with antimicrobial activity and cell selectivity. AMPs with the appropriate hydrophobicity can damage the membrane structure, causing cell lysis (Yang et al, 2019); (3). Since the negatively charged components are the first line of the cell membrane that AMPs interact with, the effects of the positive charge on the antimicrobial potency are evident (Lyu et al, 2019); and (4).The killing domain of the hybrid peptide affects structural parameters, resulting in different antimicrobial potencies (Eckert et al, 2006;Ma et al, 2015).…”

A Novel Dual-Targeted α-Helical Peptide With Potent Antifungal Activity Against Fluconazole-Resistant Candida albicans Clinical Isolates

“…The guanidinium group of Arg has more dispersed positive charges than the single amine of Lys. This property enhances peptide-membrane electrostatic interactions that result in improved antimicrobial activities ( Liu et al, 2007 ; Yang et al, 2019 ). Aromatic residues play an essential role in peptide membrane anchoring abilities ( Marsh et al, 2007 ).…”

“…The antifungal activity of the peptide was determined using the broth microdilution method previously described ( Yang et al, 2019 ). FLU (Sigma-Aldrich, Shanghai, China) and amphotericin B (AmB) (Sigma-Aldrich, St. Louis, MO, United States) were used as controls to compare the antifungal efficacies of the designed peptides.…”

“…In addition to the ability to fight against microbes, some AMPs exhibit antioxidant, anti-inflammatory, and wound healing properties ( Harioudh et al, 2017 ; Williams et al, 2018 ; Dou et al, 2019 ). Studies aimed at improving the antibacterial activities of AMPs and confirming the efficacy of antibacterial peptides designed by sequence modifications from naturally occurring, templated peptides or de novo design of a few amino acids have been done ( Shao et al, 2018 ; Yang et al, 2019 , 2020 ). However, the antifungal activities of the AMPs have only been partially explored.…”