Project description:Antimicrobial peptides (AMPs) are a group of molecules that occur naturally in all living organisms and help them to defend against various pathogens, including fungi, bacteria and viruses (Gan et al., 2021). AMPs have a low molecular mass (~2-50 amino acids), are rich in hydrophobic amino acids and have a net positive charge (Huan et al., 2020). Some stable antimicrobial peptides can bind to chitin, an insoluble homopolymer present in several types of biological materials, such as the cell wall of fungi, insects and crustacean shells; however, chitin is not present in plants. Some peptides, including chitinases, vicilins, lectins, 2S albumins and hevein-like peptides, can bind to a matrix composed of chitin. These peptides exhibit antimicrobial activity against bacteria and fungal pathogens, and they interact with fungal chitin through the chitin binding site, which plays a significant role in inhibiting fungal growth (Slezina and Odintsova, 2023). The binding site shares structural similarity with hevein, an antimicrobial peptide from the latex of Hevea brasiliensis (Willd. exA. Juss.) Müll. Arg. The main element of all hevein-like peptides is that a conservative chitin-binding site is one of their essential structural modules (Slavokhotova et al., 2017; Azmil et al., 2021). Hevein-like peptides are AMPs that are rich in cysteine, contain 29-45 amino acids and 5-7 residues contain glycine. A main feature of hevein-like peptides is a conservative chitin binding site with the amino acid sequence SXFGY/SXYGY, in which X is any amino acid residue (Beintema, 1994). In addition, these peptides are present in the plant cysteine-rich antimicrobial peptide superfamily, are 2-6 kDa in weight, contain 6-10 Cys residues and contain three to five disulfide bridges (Tam et al., 2015). They also possess structural motifs composed of three antiparallel beta sheets and a short α-helix, which are stabilized by 3-5 disulfide bonds (Odintsova et al., 2020). Previously, hevein-like peptides have been reported to exhibit activity against several fungal microorganisms with or without chitin in their cell wall (Slezina and Odintsova, 2023). The mechanism underlying the activity of hevein-like peptides is mainly through depolarization of hyphae membrane (Azmil et al., 2021). Recently, several hevein-like peptides have been isolated from several plant species, such as wheat (Odintsova et al., 2020), quinoa (Loo et al., 2021) and moringa (Sousa et al., 2020). These peptides exhibited activity against a range of microorganisms, such as F. oxysporum, F. culmorum, Bipolaris sorokininana, Alternaria alternata and Cladosporium cucumerinum (Odintsova et al., 2020). These findings have encouraged further studies on the application of these molecules against pathogenic fungi, as the molecules exhibit great activity and could be used to create new antifungal medications. Peppers and chilies originate from the tropical Americas and belong to 22 families of Solanaceae and the genus Capsicum; 35 of these species have been domesticated, while the others remain semidomesticated and wild. The plants are dispersed worldwide, and in Brazil, they are cultivated mainly in the states of Rio de Janeiro, Minas Gerais, Bahia and Goiás; among the various locations, Rio de Janeiro is a special center of diversity (Moscone et al., 2006). These plants are essential solanaceous vegetables with high world economic value. However, the growth, quality and yield of these plants are reduced by biotic (fungal, bactéria and virus infections and pests) and abiotic (drought, salinity and extreme temperatures) factors (Mittler, 2006; Wang et al., 2003). Several AMPs have been isolated from different organs of plants within the Capsicum genus (Oliveira et al., 2022). For example, a hevein-like peptide was identified from C. annuum leaves; this peptide is approximately 4.2 kDa and was named HEVCAN. In addition, the peptide belongs to the chitin-binding domain family and exhibits antimicrobial activity (Oliveira et al., 2022). Our research group has previously isolated and identified several other antimicrobial peptides, such as defensin (Gebara et al., 2020), LTP (Diz et al., 2011), protease inhibitors (Ribeiro et al., 2013) and chitin-binding peptides (Gonçalves et al., 2024), from Capsicum seeds. In this study, we used a chitin affinity column to purify peptide fractions from C. chinense seeds, and these fractions exhibited chitin-binding capacity and activity against yeasts.
2024-10-17 | PXD054607 | Pride
Leslie Hicks 
