Sequential and Structural Aspects of Antifungal Peptides from Animals, Bacteria and Fungi Based on Bioinformatics Tools

Abstract

Emerging drug resistance varieties and hyper-virulent strains of microorganisms have compelled the scientific fraternity to develop more potent and less harmful therapeutics. Antimicrobial peptides could be one of such therapeutics. This review is an attempt to explore antifungal peptides naturally produced by prokaryotes as well as eukaryotes. They are components of innate immune system providing first line of defence against microbial attacks, especially in eukaryotes. The present article concentrates on types, structures, sources and mode of action of gene-encoded antifungal peptides such as mammalian defensins, protegrins, tritrpticins, histatins, lactoferricins, antifungal peptides derived from birds, amphibians, insects, fungi, bacteria and their synthetic analogues such as pexiganan, omiganan, echinocandins and Novexatin. In silico drug designing, a major revolution in the area of therapeutics, facilitates drug development by exploiting different bioinformatics tools. With this view, bioinformatics tools were used to visualize the structural details of antifungal peptides and to predict their level of similarity. Current practices and recent developments in this area have also been discussed briefly.

Antimicrobial and Antibiofilm Peptides

“…According to their mechanism of action and origin, antifungal peptides can be grouped into membrane-traversing peptides, which can lead to pore formation or act on β-glucan or chitin synthesis, and non-membrane-traversing peptides that interact with the cell membrane and cause cell lysis [67]. Antifungal peptides can lead to fungi death through different mechanisms of action, including inhibition of DNA, RNA, and protein synthesis; induction of apoptotic mechanisms; permeabilization of membranes; inhibition of cell wall synthesis and enzyme activity; or repression of protein folding and metabolic turnover [68,69].…”

Natural Antimicrobial Peptides as Inspiration for Design of a New Generation Antifungal Compounds

“…Antifungal peptides have diverse action mechanisms, which include: (1) inhibition of DNA, RNA and protein synthesis; (2) binding to DNA or RNA; (3) membrane permeabilization; (4) inhibition of the cell wall synthesis and enzyme activity; (5) induction of apoptosis; and (6) repression of protein folding and metabolic turnover [ 49 , 53 , 54 , 55 ]. Antifungal peptides can be classified according to their mode of action and origin [ 56 ]. Based on their action mechanism, antifungal peptides can be divided into: (1) membrane traversing peptides that can cause pore formation or act on specific target such as β-glucan or chitin synthesis; and (2) non membrane traversing peptides that interact with the cell membrane and cause cell lysis [ 56 ].…”

“…Antifungal peptides can be classified according to their mode of action and origin [ 56 ]. Based on their action mechanism, antifungal peptides can be divided into: (1) membrane traversing peptides that can cause pore formation or act on specific target such as β-glucan or chitin synthesis; and (2) non membrane traversing peptides that interact with the cell membrane and cause cell lysis [ 56 ]. According to their origin, peptides can be classified as natural compounds and synthetic molecules isolated from genetic or recombinant libraries or discovered from chemical libraries [ 56 , 57 ].…”

“…syringae or iturins produced by Bacillus subtilis are lytic peptides active against broad spectrum of yeasts and filamentous fungi [ 84 , 85 , 86 , 137 ]. Iturins affect membrane surface and create tension, which cause pore formation, leakage of K + and other ions, resulting in cell death [ 56 ]. Despite iturins are highly active against C. albicans , A. niger , Trichosporon spp., and Fusarium oxysporum , their utilization in antifungal therapy is restricted because of hemotoxicity [ 86 , 89 ].…”

“…They are a family of cationic antimicrobial peptides, first isolated from silk moth ( Hyalophora cecropia ). Cecropins exert their antifungal activity by targeting and lysing fungal plasma membrane [ 56 ]. They are highly fungicidal against blastoconidial cells of C. albicans , Aspergillus spp.…”