Computational Screening for the Anticancer Potential of Seed-Derived Antioxidant Peptides: A Cheminformatic Approach

Novel and efficient techniques in the discovery of antioxidant peptides

As a research hotspot in food science and nutrition, antioxidant peptides can function by scavenging free radicals, inhibiting peroxides, and chelating metal ions. Therefore, how to efficiently discover and screen antioxidant peptides has become a key issue in research and production. Traditional discovery methods are time-consuming and costly, but also challenging to resolve the quantitative structure-activity relationship of antioxidant peptides. Several novel techniques, including artificial intelligence, molecular docking, bioinformatics, quantum chemistry, phage display, switchSENSE, surface plasmon resonance, and fluorescence polarization, are emerging rapidly as solutions. These techniques possess efficient capability for the discovery of antioxidant peptides, even with the potential for high-throughput screening. In addition, the quantitative structure-activity relationship can be resolved. Notably, combining these novel techniques can overcome the drawbacks of a single one, thus improving efficiency and expanding the discovery horizon. This review has summarized eight novel and efficient techniques for discovering antioxidant peptides and the combination of techniques. This review aims to provide scientific evidence and perspectives for antioxidant peptide research.

Purification, identification and molecular docking studies of antioxidant and anti-inflammatory peptides from Edible Bird's Nest

This study investigated antioxidant and anti-inflammatory peptides from Edible Bird's Nest (EBN). The prepared EBN peptides were sequentially separated, purified, and successively identified by ultrafiltration, gel filtration and mass spectrometry techniques. Four potential antioxidant and anti-inflammatory peptides were identified as Peptide 1 (LFWSPSVYLK), Peptide 2 (GWPHLEDNYLDW), Peptide 3 (NPPADLHK) and Peptide 4 (GDLAYLDQGHR). Molecular docking analysis revealed that Peptide 1 and Peptide 2 can competitively interrupt the formation of Keap1-Nrf2 due to the presence of hydrophobic and antioxidant amino acids in their peptide sequences. Peptide 3 and Peptide 4 have a strong effect on interacting with the binding site of IKK-β due to the interaction of anti-inflammatory amino acids and C-terminal arginine/lysine. The four peptides were synthesised and validated for their antioxidant and anti-inflammatory activities. The results suggest that the four peptides may serve as promising bioactive peptides for preventing oxidative stress and inflammation-related diseases.

Efficient screening of pharmacological broad-spectrum anti-cancer peptides utilizing advanced bidirectional Encoder representation from Transformers strategy

In the vanguard of oncological advancement, this investigation delineates the integration of deep learning paradigms to refine the screening process for Anticancer Peptides (ACPs), epitomizing a new frontier in broad-spectrum oncolytic therapeutics renowned for their targeted antitumor efficacy and specificity. Conventional methodologies for ACP identification are marred by prohibitive time and financial exigencies, representing a formidable impediment to the evolution of precision oncology. In response, our research heralds the development of a groundbreaking screening apparatus that marries Natural Language Processing (NLP) with the Pseudo Amino Acid Composition (PseAAC) technique, thereby inaugurating a comprehensive ACP compendium for the extraction of quintessential primary and secondary structural attributes. This innovative methodological approach is augmented by an optimized BERT model, meticulously calibrated for ACP detection, which conspicuously surpasses existing BERT variants and traditional machine learning algorithms in both accuracy and selectivity. Subjected to rigorous validation via five-fold cross-validation and external assessment, our model exhibited exemplary performance, boasting an average Area Under the Curve (AUC) of 0.9726 and an F1 score of 0.9385, with external validation further affirming its prowess (AUC of 0.9848 and F1 of 0.9371). These findings vividly underscore the method's unparalleled efficacy and prospective utility in the precise identification and prognostication of ACPs, significantly ameliorating the financial and temporal burdens traditionally associated with ACP research and development. Ergo, this pioneering screening paradigm promises to catalyze the discovery and clinical application of ACPs, constituting a seminal stride towards the realization of more efficacious and economically viable precision oncology interventions.

Novel antioxidant peptides identified from coix seed by molecular docking, quantum chemical calculations and invitro study in HepG2 cells

The aim of the study was to identify potent antioxidant peptides sourced from coix seed, analyze the structure-activity relationship through molecular docking and quantum chemical calculation. Molecular docking results showed that among thirteen peptides selected in silico, eight had favourable binding interaction with the Keap1-Kelch domain (2FLU). Promising peptides with significant binding scores were further evaluated using quantum calculation. It was shown that peptide FFDR exhibited exceptional stability, with a high energy gap of 5.24 eV and low Highest Occupied Molecular Orbitals (HOMO) and Lowest Unoccupied Molecular Orbitals (LUMO) values. Furthermore, FFDR displayed the capacity to enhance the expression of Nrf2-Keap1 antioxidant genes (CAT, SOD, GSH-Px) and improved cellular redox balance by increasing reduced glutathione (GSH) while reducing oxidized glutathione (GSSG) and malonaldehyde (MDA) levels. These findings highlight the potential of coix seed peptides in developing novel, effective and stable antioxidant-based functional foods.

Virtual Screening of Peptide Libraries: The Search for Peptide-Based Therapeutics Using Computational Tools

Over the last few decades, we have witnessed growing interest from both academic and industrial laboratories in peptides as possible therapeutics. Bioactive peptides have a high potential to treat various diseases with specificity and biological safety. Compared to small molecules, peptides represent better candidates as inhibitors (or general modulators) of key protein-protein interactions. In fact, undruggable proteins containing large and smooth surfaces can be more easily targeted with the conformational plasticity of peptides. The discovery of bioactive peptides, working against disease-relevant protein targets, generally requires the high-throughput screening of large libraries, and in silico approaches are highly exploited for their low-cost incidence and efficiency. The present review reports on the potential challenges linked to the employment of peptides as therapeutics and describes computational approaches, mainly structure-based virtual screening (SBVS), to support the identification of novel peptides for therapeutic implementations. Cutting-edge SBVS strategies are reviewed along with examples of applications focused on diverse classes of bioactive peptides (i.e., anticancer, antimicrobial/antiviral peptides, peptides blocking amyloid fiber formation).

Bioactive peptides derived from Radix Angelicae sinensis inhibit ferroptosis in HT22 cells through direct Keap1-Nrf2 PPI inhibition

The development of natural peptides as direct Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid2-related factor 2 (Nrf2) protein-protein interaction (PPI) inhibitors for antioxidant and anti-ferroptotic purposes has attracted increasing interest from chemists. Radix Angelicae sinensis (RAS) is a widely used traditional Chinese medicine with antioxidant capability. However, few studies have screened Keap1-Nrf2 PPI inhibitory RAS peptides (RASPs). This study optimized the extraction and hydrolysis protocols of RAS protein using response surface methodology coupled with Box-Behnken design. The molecular weight distribution of the prepared hydrolysates was analysed to obtain active fractions. Subsequently, ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry was employed to identify RASPs. Various in vitro and in silico assays were conducted to evaluate the antioxidant and anti-ferroptotic effects of RASPs. The results revealed that at least 50 RASPs could be obtained through the optimized protocols. RASPs containing active residues effectively scavenged 2,2-diphenyl-1-picrylhydrazyl radical and 2,2'-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid radical cation. They also showed cytoprotective effect against erastin-induced ferroptosis in HT22 cells, which was characterized by the activation of Nrf2 and weakened under the incubation of an Nrf2 inhibitor. Moreover, RASPs could bind to Keap1 and then dissociate Nrf2 in molecular dynamics simulations. In conclusion, RASPs exhibit antioxidant activity through hydrogen atom transfer and electron transfer mechanisms. Importantly, they also inhibit ferroptosis by directly inhibiting Keap1-Nrf2 PPI.

Computational approaches for molecular characterization and structure-based functional elucidation of a hypothetical protein from Mycobacterium tuberculosis

Adaptation of infections and hosts has resulted in several metabolic mechanisms adopted by intracellular pathogens to combat the defense responses and the lack of fuel during infection. Human tuberculosis caused by Mycobacterium tuberculosis (MTB) is the world's first cause of mortality tied to a single disease. This study aims to characterize and anticipate potential antigen characteristics for promising vaccine candidates for the hypothetical protein of MTB through computational strategies. The protein is associated with the catalyzation of dithiol oxidation and/or disulfide reduction because of the protein's anticipated disulfide oxidoreductase properties. This investigation analyzed the protein's physicochemical characteristics, protein-protein interactions, subcellular locations, anticipated active sites, secondary and tertiary structures, allergenicity, antigenicity, and toxicity properties. The protein has significant active amino acid residues with no allergenicity, elevated antigenicity, and no toxicity.

Exploring the Potential of Black Soldier Fly Larval Proteins as Bioactive Peptide Sources through in Silico Gastrointestinal Proteolysis: A Cheminformatic Investigation

Despite their potential as a protein source for human consumption, the health benefits of black soldier fly larvae (BSFL) proteins following human gastrointestinal (GI) digestion are poorly understood. This computational study explored the potential of BSFL proteins to release health-promoting peptides after human GI digestion. Twenty-six proteins were virtually proteolyzed with GI proteases. The resultant peptides were screened for high GI absorption and non-toxicity. Shortlisted peptides were searched against the BIOPEP-UWM and Scopus databases to identify their bioactivities. The potential of the peptides as inhibitors of myeloperoxidase (MPO), NADPH oxidase (NOX), and xanthine oxidase (XO), as well as a disruptor of Keap1–Nrf2 protein–protein interaction, were predicted using molecular docking and dynamics simulation. Our results revealed that about 95% of the 5218 fragments generated from the proteolysis of BSFL proteins came from muscle proteins. Dipeptides comprised the largest group (about 25%) of fragments arising from each muscular protein. Screening of 1994 di- and tripeptides using SwissADME and STopTox tools revealed 65 unique sequences with high GI absorption and non-toxicity. A search of the databases identified 16 antioxidant peptides, 14 anti-angiotensin-converting enzyme peptides, and 17 anti-dipeptidyl peptidase IV peptides among these sequences. Results from molecular docking and dynamic simulation suggest that the dipeptide DF has the potential to inhibit Keap1–Nrf2 interaction and interact with MPO within a short time frame, whereas the dipeptide TF shows promise as an XO inhibitor. BSFL peptides were likely weak NOX inhibitors. Our in silico results suggest that upon GI digestion, BSFL proteins may yield high-GI-absorbed and non-toxic peptides with potential health benefits. This study is the first to investigate the bioactivity of peptides liberated from BSFL proteins following human GI digestion. Our findings provide a basis for further investigations into the potential use of BSFL proteins as a functional food ingredient with significant health benefits.

From In Silico to a Cellular Model: Molecular Docking Approach to Evaluate Antioxidant Bioactive Peptides

The increasing need to counteract the redox imbalance in chronic diseases leads to focusing research on compounds with antioxidant activity. Among natural molecules with health-promoting effects on many body functions, bioactive peptides are gaining interest. They are protein fragments of 2–20 amino acids that can be released by various mechanisms, such as gastrointestinal digestion, food processing and microbial fermentation. Recent studies report the effects of bioactive peptides in the cellular environment, and there is evidence that these compounds can exert their action by modulating specific pathways. This review focuses on the newest approaches to the structure–function correlation of the antioxidant bioactive peptides, considering their molecular mechanism, by evaluating the activation of specific signaling pathways that are linked to antioxidant systems. The correlation between the results of in silico molecular docking analysis and the effects in a cellular model was highlighted. This knowledge is fundamental in order to propose the use of bioactive peptides as ingredients in functional foods or nutraceuticals.

Redox Active Molecules in Cancer Treatments

Cancer is one of the leading causes of death worldwide, with nearly 10 million deaths in 2020 [...].

Open-Source Browser-Based Tools for Structure-Based Computer-Aided Drug Discovery

We here outline the importance of open-source, accessible tools for computer-aided drug discovery (CADD). We begin with a discussion of drug discovery in general to provide context for a subsequent discussion of structure-based CADD applied to small-molecule ligand discovery. Next, we identify usability challenges common to many open-source CADD tools. To address these challenges, we propose a browser-based approach to CADD tool deployment in which CADD calculations run in modern web browsers on users' local computers. The browser app approach eliminates the need for user-initiated download and installation, ensures broad operating system compatibility, enables easy updates, and provides a user-friendly graphical user interface. Unlike server apps-which run calculations "in the cloud" rather than on users' local computers-browser apps do not require users to upload proprietary information to a third-party (remote) server. They also eliminate the need for the difficult-to-maintain computer infrastructure required to run user-initiated calculations remotely. We conclude by describing some CADD browser apps developed in our lab, which illustrate the utility of this approach. Aside from introducing readers to these specific tools, we are hopeful that this review highlights the need for additional browser-compatible, user-friendly CADD software.

Purification and Identification of Novel Myeloperoxidase Inhibitory Antioxidant Peptides from Tuna (Thunnas albacares) Protein Hydrolysates

Antioxidative peptides that inhibit myeloperoxidase (MPO) enzyme activity can effectively defend against oxidative stress damage. The antioxidant peptides from tuna protein were produced using alcalase hydrolysis and purified by ultrafiltration and Sephadex G-15, and the fractions with the highest free radicals scavenging ability and oxygen radical absorbance capacity (ORAC) values were sequenced using HPLC–MS/MS. Fifty-five peptide sequences were identified, 53 of which were successfully docked into MPO. The representative peptide ACGSDGK had better antioxidant activity and inhibition of MPO chlorination and peroxidation than the reference peptide hLF1-11. The docking model further showed intense molecular interactions between ACGSDGK and MPO, including hydrogen bonds, charge, and salt bridge interactions, which occluded the active site and blocked the catalytic activity of MPO. These results suggested that the antioxidant peptide ACGSDGK has the potential to inhibit oxidative stress and alleviate inflammation in vivo because of its inhibitory effect on the MPO enzyme.