Production and characterization of antioxidative peptides during lactic fermentation of goat milk

Peptidomics-based identification of an antimicrobial peptide derived from goat milk fermented by Lactobacillus rhamnosus (C25)

Antimicrobial peptides (AMPs) are emerging as promising novel drug applicants. In the present study, goat milk was fermented using Lactobacillus rhamnosus C25 to generate bioactive peptides (BAPs). The peptide fractions generated were separated using ultrafiltration membranes with molecular weight cut-offs of 3, 5, and 10 kDa, and their antimicrobial activity toward Gram-positive and Gram-negative bacteria was investigated. Isolated AMPs were characterized using RP-HPLC and identified by LC-MS/MS. A total of 569 sequences of peptides were identified by mass spectrometry. Out of the 569, 36 were predicted as AMPs, 21 were predicted as cationic, and out of 21, 6 AMPs were helical peptides. In silico analysis indicated that the majority of peptides were antimicrobial and cationic in nature, an important factor for peptide interaction with the negative charge membrane of bacteria. The results showed that the peptides of <5 kDa exhibited maximum antibacterial activity against E. faecalis, E. coli, and S. typhi. Further, molecular docking was used to evaluate the potent MurD ligase inhibitors. On the basis of ligand binding energy, six predicted AMPs were selected and then analyzed by AutoDock tools. Among the six AMPs, peptides IGHFKLIFSLLRV (-7.5 kcal/mol) and KSFCPAPVAPPPPT (-7.6 kcal/mol), were predicted as a high-potent antimicrobial. Based on these findings, in silico investigations reveal that proteins of goat milk are a potential source of AMPs. This is for the first time that the antimicrobial peptides produced by Lactobacillus rhamnosus (C25) fermentation of goat milk have been identified via LC-MS/MS and predicted as AMPs, cationic charges, helical structure in nature, and potent MurD ligase inhibitors. These peptides can be synthesized and improved for use as antimicrobial agents. PRACTICAL APPLICATIONS: Goat milk is considered a high-quality source of milk protein. According to this study, goat milk protein is a potential source of AMPs, Fermentation can yield goat milk-derived peptides with a broad antibacterial activity spectrum at a low cost. The approach described here could be beneficial in that the significant AMPs can be synthesized and used in the pharmaceutical and food industries.

Protein-protein interaction prediction with deep learning: A comprehensive review

Most proteins perform their biological function by interacting with themselves or other molecules. Thus, one may obtain biological insights into protein functions, disease prevalence, and therapy development by identifying protein-protein interactions (PPI). However, finding the interacting and non-interacting protein pairs through experimental approaches is labour-intensive and time-consuming, owing to the variety of proteins. Hence, protein-protein interaction and protein-ligand binding problems have drawn attention in the fields of bioinformatics and computer-aided drug discovery. Deep learning methods paved the way for scientists to predict the 3-D structure of proteins from genomes, predict the functions and attributes of a protein, and modify and design new proteins to provide desired functions. This review focuses on recent deep learning methods applied to problems including predicting protein functions, protein-protein interaction and their sites, protein-ligand binding, and protein design.

Conventional and Novel Technologies in the Production of Dairy Bioactive Peptides

Background

In recent years, researchers have focused on functional ingredients, functional foods, and nutraceuticals due to the rapidly increasing interest in bioactive components, especially in bioactive peptides. Dairy proteins are a rich and balanced source of amino acids and their derived bioactive peptides, which possess biological and physiological properties. In the dairy industry, microbial fermentation and enzymatic hydrolysis are promising methods for producing bioactive peptides because of their rapid efficiency, and mild reaction conditions. However, these methods utilize less raw material, take long reaction time, result in low yields, and low activity products when used alone, which pose industry to seek for novel methods as pretreatments to increase the yield of bioactive peptides.

Scope and Approach

This review emphasizes the production of peptides from the dairy proteins and discusses the potential use of novel technologies as pretreatments to conventional methods of bioactive peptides production from dairy proteins, including the mechanisms of novel technologies along with respective examples of use, advantages, limitations, and challenges to each technology.

Key Findings and Conclusion

Noteworthily, hydrolysis of dairy proteins liberate wide-range of peptides that possess remarkable biological functions to maintain human health. Novel technologies in the dairy industry such as ultrasound-assisted processing (UAP), microwave-assisted processing (MAP), and high pressure processing (HPP) are innovative and environmentally friendly. Generally, novel technologies are less effectual compared to conventional methods, therefore used in combination with fermentation and enzymatic hydrolysis, and are promising pretreatments to modify peptides’ profile, improve the yields, and high liberation of bioactive peptides as compared to conventional technologies. UAP is an innovative and most efficient technology as its mechanical effects and cavitation change the protein conformation, increase the biological activities of enzymes, and enhance enzymatic hydrolysis reaction rate.