Inhibitory Peptide Research Articles

Structure characterization and mechanism of angiotensin I-converting enzyme (ACE) inhibitory peptides modified by plastein reaction derived from tiger nut (Cyperus esculentus)

The development of peptides derived from plants, which have potential anti-angiotensin converting enzyme (ACE) activity and other bioactivities, are of scientific interest. ACE inhibitory peptide (CLPP, the ACE inhibitory rate is 76.52 ± 1.07%) was obtained by hydrolysis of tiger nut (Cyperus esculentus) protein with alkaline protease. The plastein product (PCLPP, the ACE inhibitory rate is 85 ± 2.33%) was prepared by modifying CLPP with a plastein reaction. The results of SEM, IR, and XRD show that the structure of PCLPP is different from that of CLPP. The results of differential scanning calorimetry, fluorescence, and free amino analysis showed that the reaction was carried out by aggregation and condensation. These results suggest that the plastein reaction may be an effective method to increase the variety of bioactive peptides.

Uncovering novel KCC2 regulatory motifs through a comprehensive transposon-based mutant library

IntroductionThe neuron-specific K-Cl cotransporter KCC2 maintains low intracellular chloride levels, which are crucial for fast GABAergic and glycinergic neurotransmission. KCC2 also plays a pivotal role in the development of excitatory glutamatergic neurotransmission by promoting dendritic spine maturation. The cytoplasmic C-terminal domain (KCC2-CTD) plays a critical regulatory role in the molecular mechanisms controlling the cotransporter activity through dimerization, phosphorylation, and protein interaction.MethodsTo identify novel CTD regulatory motifs, we used the Mu transposon-based mutagenesis system to generate a library of KCC2 mutants with 5 amino acid insertions randomly distributed within the KCC2-CTD. We determined the insertion positions in 288 mutants by restriction analysis and selected clones with a single insertion site outside known KCC2 regulatory motifs. We analyzed the subcellular distribution of KCC2-CTD mutants in cultured cortical neurons using immunocytochemistry and selected ten mutants with ectopic expression patterns for detailed characterization.ResultsA fluorescent Cl−-transport assay in HEK293 cells revealed mutants with both reduced and enhanced Cl−-extrusion activity, which overall correlated with their glycosylation patterns. Live-cell immunostaining analysis of plasma membrane expression of KCC2-CTD mutants in cultured cortical neurons corroborated the glycosylation data. Furthermore, the somatodendritic chloride gradient in neurons transfected with the KCC2-CTD mutants correlated with their Cl−-extrusion activity in HEK293 cells. Gain- and loss-of-function mutant positions were analyzed using available KCC2 cryo-EM structures.DiscussionTwo groups of mutants were identified based on 3D structural analysis. The first group, located near the interface of transmembrane and cytoplasmic domains, may affect interactions with the N-terminal inhibitory peptide regulating KCC2 activity. The second group, situated on the external surface of the cytoplasmic domain, may disrupt interactions with regulatory proteins. Analyzing CTD mutations that modulate KCC2 activity enhances our understanding of its function and is essential for developing novel anti-seizure therapies.

Glycyrrhetinic acid prohibiting fusion peptides from fusing with cell membrane

The inhibition of the fusion peptide (FP) of the spike protein of coronaviruses, which mediates interactions with the host cell membrane, plays a critical role in the membrane fusion process. In this study, we investigated the interactions between the FP and cell membranes and evaluated the effect of three drug molecules — neferine (Nef), glycyrrhetinic acid (GA), quercetin (Qct) on the membrane fusion process by combining molecular dynamic (MD) simulations and experimental methods. Our findings revealed that glycyrrhetinic acid exhibited strong binding ability towards the FP (residues 815‐828), with particularly interactions observed with key residues L821, L822, F823, and L828. Furthermore, we performed FITC fluorescence staining experiments on cells and assessed the inhibitory effects of glycyrrhetinic acid on FP. The results showed a significant reduction in fluorescence intensity in the FP‐FITC experiment group treated with glycyrrhetinic acid, indicating that glycyrrhetinic acid interferes with the binding ability of FP and disrupts its localization on the cell membrane. Overall, this research will contribute to a deeper understanding of the inhibition mechanism of FP’s membrane fusion process, which widely exists in the intrusion process between viruses and cells.

Rapid discovery of cyclic peptide protein aggregation inhibitors by continuous selection.

Protein aggregates are associated with numerous diseases. Here we report a platform for the rapid phenotypic selection of protein aggregation inhibitors from genetically encoded cyclic peptide libraries in Escherichia coli based on phage-assisted continuous evolution (PACE). We developed a new PACE-compatible selection for protein aggregation inhibition and used it to identify cyclic peptides that suppress amyloid-β42 and human islet amyloid polypeptide aggregation. Additionally, we integrated a negative selection that removes false positives and off-target hits, greatly improving cyclic peptide selectivity. We show that selected inhibitors are active when chemically resynthesized in in vitro assays. Our platform provides a powerful approach for the rapid discovery of cyclic peptide inhibitors of protein aggregation and may serve as the basis for the future evolution of cyclic peptides with a broad spectrum of inhibitory activities.

In Silico, Molecular Docking and In Vitro angiotensin-converting enzyme-inhibitory activity of PGYALQR peptide derived from fish waste hydrolysate

In recent decades, Angiotensin-converting enzyme (ACE) inhibitory peptides derived from various proteins have become crucial sources of health-enhancing components for clinical use. Abundant proteins in fish waste entrails can be used to produce ACE inhibitory peptides. Catfish, Tilapia, and Mackerel entrails were digested by pepsin and passed through the 3kDa cutoff column. The protein hydrolysate passed through the 3kDa cutoff column and C18 column were analyzed for an ACE inhibitory activities and sequenced using LC-MS/MS. Five candidate peptides from De novo sequencing was chemically synthesized and tested for ACE inhibitory activity. The ACE inhibitory activity result revealed that PGYALQR peptide contains ACE inhibitory activity as captopril did. This study aims to predict the conformation and orientation of the PGYALQR peptide into the binding site of ACE. Molecular docking analysis using AutoDock Vina was performed to elucidate the mechanisms underlying the ACE-inhibitory activity of the PGYALQR peptide. Computational analysis revealed that the peptide binds to the ACE active site with −11.2 kcal/mol, forming hydrogen bonds with Glu162, Gln281, His353, Ala354, Lys511, His513, and Tyr523. In comparision, captopril interacted with Gln281, His353, Lys511, His513, Tyr520, and Tyr523 with a binding energy of −5.9 kcal/mol. Additionally, the peptide interacts with the Zn (II) ion in the ACE active site, coordinating with the residues Glu411, His383, and His387, which is crucial for enhancing its inhibitory activity of ACE. It may contort the tetrahedral coordination of the Zn (II), resulting in loss of ACE activity.

Novel peptide inhibitor of matrix Metalloproteinases-1 from pufferfish skin collagen hydrolysates and its potential Photoprotective activity via the MAPK/AP-1 signaling pathway.

Takifugu bimaculatus, a pufferfish species farmed in Fujian Province, is known for its non-toxic flesh and collagen-rich skin. We identified a novel collagen-derived matrix metalloproteinase 1 (MMP-1) inhibitory peptide, from T. bimaculatus skin with potent anti-photoaging properties. Using multistage membrane and gel filtration chromatography, we purified low-molecular-weight collagen peptides from T. bimaculatus skin (TBSCH-L). Nano-HPLC-MS/MS and virtual molecular docking screening were employed to identify peptides targeting MMP-1. Four anti-photoaging peptide sequences, GDRGFPGE, GPAGPRGA, FPGGPGAK, and RGFPGGDGAA, were identified by assessing the viability of UVB-induced L929 cells. GPAGPRGA (GP8) exhibited the highest MMP-1 inhibitory activity and cellular photoprotection. Surface plasmon resonance confirmed high-affinity binding between MMP-1 and GP8. GP8 significantly reduced intracellular reactive oxygen species (ROS) levels and enhanced superoxide dismutase activity at concentrations of 100-200μM in UVB-exposed L929 cells. At 200μM, GP8 significantly decreased malondialdehyde content. GP8 also accelerated migration of L929 cells, demonstrating its wound-healing potential, markedly reduced intracellular β-galactosidase levels, and downregulated phosphorylation levels of extracellular signal-regulated kinases, c-Jun N-terminal kinases, p38 proteins, and c-Jun protein expression within the MAPK/AP-1 signaling pathway, thereby lowering MMP expression in L929 cells. Exposure of zebrafish to 25-100μM GP8 effectively mitigated UVB-induced damage, restoring up to 31.2% of caudal fin integrity, while significantly reducing ROS levels, lipid peroxidation, and cellular apoptosis. GP8, a novel marine-derived anti-photoaging peptide, holds promise for applications in cosmetic and functional food sectors.

A novel angiotensin I-converting enzyme (ACE) inhibitory peptide from Wuyi rock tea residue: Preparation, identification, and its potential molecular mechanism

A novel angiotensin I-converting enzyme (ACE) inhibitory peptide from Wuyi rock tea residue: Preparation, identification, and its potential molecular mechanism

Integrated network pharmacology and experimental validation to explore the mechanisms of Coregonus peled-derived myosin ACE-inhibiting peptides for the treatment of hypertension

Coregonus peled is rich in protein and is a plentiful resource of bioactive peptides. This study was aimed at extracting novel Angiotensin I-converting enzyme (ACE) inhibitory peptides from Coregonus peled and revealing their potential hypotensive mechanisms. This paper screened six ACE inhibitory peptides with high bioactivity, good water solubility, and ADMET properties by computerized enzyme digestion of myosin-heavy chain from Coregonus peled, and LCYPR had the greatest ACE inhibition activity (IC50 = 47.8782 μM). There were 47 potentially critical targets of LCYPR for hypertension treatment, involving 135 biological processes (BP), 30 cellular components (CC), and 30 molecular functions (MF). The results of KEGG pathway analyse showed that the LCYPR participated in 50 pathways including the renin-angiotensin system, renin secretion, lipid and atherosclerosis, relaxin signaling pathway, IL-17 signaling pathway, atherosclerosis, fluid shear stress, and others, through the key targets such as AGT, AKT1, ACE, REN, CTSB, STAT3, PLG, SRC, MMP2, and F2 to regulate the blood pressure of organisms. In conclusion, the study obtained a novel ACE inhibitory peptide from the myosin-heavy chain of Coregonus peled and revealed the potential target and pathway of LCYPR to improve hypertension. The study provides new ideas and methods for developing novel antihypertensive peptides. The results provide a theoretical basis for developing functional foods of the Xinjiang specialty cold-water fish.

Multiple Biomarkers to Predict Major Adverse Cardiovascular Events in Patients With Coronary Chronic Total Occlusions.

There are limited tools available to predict the long-term prognosis of persons with coronary chronic total occlusions (CTO). A previously-described blood biomarker panel to predict cardiovascular (CV) events was evaluated in patients with CTO. From 1251 patients in the CASABLANCA study, 241 participants with a CTO were followed for an average of 4 years for occurrence of major adverse CV events (MACE, CV death, non-fatal myocardial infarction or stroke) and CV death/heart failure (HF) hospitalization. Results of a biomarker panel (kidney injury molecule-1, N-terminal pro-B-type natriuretic peptide, osteopontin, and tissue inhibitor of metalloproteinase-1) from baseline samples were expressed as low-, medium-, and high-risk. By 4 years, a total of 67 (27.8%) MACE and 56 (23.2%) CV death/HF hospitalization events occurred. The C-statistic of the panel for MACE through 4 years was 0.79 (P <0.001). Considering the low-risk group as referent, the hazard ratio (HR) of MACE by 4 years was 6.65 (95% confidence interval [CI]: 2.98-14.8) and 12.4 (95% CI:5.17-29.6) for the medium and high-risk groups (both P <0.001). The C-statistic for CVD/HF hospitalization by 4 years was 0.84 (P <0.001). Compared to the low-risk score group, the medium and high-risk groups had HR of 5.61 (95% CI: 2.33-13.5) and 15.6 (95% CI: 6.18, 39.2; both P value <0.001). In conclusion, a multiple biomarker panel assisted in discriminating a broad range of risk for adverse outcomes in patients with coronary CTO. These results may have implications for risk stratification, patient care and could have a role for clinical trial enrichment.

ACE inhibitory peptides and flavor compounds from Se-enriched Bacillus natto fermented chickpea

ACE inhibitory peptides and flavor compounds from Se-enriched Bacillus natto fermented chickpea

Characterization and efficient screening of natural DPP-IV inhibitory peptides from Huizhou dry-cured ham: In Silico and In Vitro studies

Characterization and efficient screening of natural DPP-IV inhibitory peptides from Huizhou dry-cured ham: In Silico and In Vitro studies

Screening, identification, and mechanistic exploration of DPP-IV inhibitory peptides from collagen in Esox lucius skin

Screening, identification, and mechanistic exploration of DPP-IV inhibitory peptides from collagen in Esox lucius skin

Structure-based method for the discovery of selective inhibitors of PED 5 in erectile dysfunction therapy from the Pacific oyster peptides (Crassostrea gigas): Peptidomic analysis, molecular docking, and activity validation.

Erectile dysfunction (ED) is a male sexual disorder mainly caused by a reduction in the cellular concentration of cyclic guanosine monophosphate (cGMP), which is degraded by phosphodiesterase type-5 (PDE-5). Oyster protein (OP) and its hydrolysates have been used for centuries to address male erectile dysfunction, however the mechanisms and evidence supporting their efficacy remain unclear. In this study, OP was hydrolyzed using trypsin to produce peptides that inhibit PDE-5. Following separation by ultrafiltration and Sephadex G-25, a total of 3202 peptides were identified. Virtual screening and molecular docking were employed to identify PDE-5 inhibitory peptides and elucidate their interaction mechanisms with PDE-5. Five peptides with the sequences FLF, LMF, LLW, FGPF, and IPW demonstrated strong interactions with PED5. The results indicated that the key binding sites critical for docking included Phe820, Gln817 and Val782 of the target receptor PED-5. The highest inhibition rate observed for FGPF was 94.6 %, while the inhibition rates for IPW and FLF were 89.0 % and 87.6 %, respectively. The lowest inhibition rate was recorded for LLW at 68 %. These findings suggest that these five peptides have the potential to serve as PDE-5 inhibitors in the health food industry and medicine.

Identification of novel xanthine oxidase inhibitory peptides from Takifugu obscurus: Peptidomic analysis, molecular docking, and dynamics simulation

Identification of novel xanthine oxidase inhibitory peptides from Takifugu obscurus: Peptidomic analysis, molecular docking, and dynamics simulation

Identification and mechanistic investigation of novel adhesion inhibitory peptides against Helicobacter pylori from corn protein hydrolysates

Identification and mechanistic investigation of novel adhesion inhibitory peptides against Helicobacter pylori from corn protein hydrolysates

Rational engineering of an antimalarial peptide with enhanced proteolytic stability and preserved parasite invasion inhibitory activity.

We describe rational chemical engineering to enhance the proteolytic stability of a chimeric peptide using a combination of unique strategies that involve the incorporation of a series of d-amino acids into the parent l-peptide sequence and restricting the conformational freedom of the peptide by covalent stitching. We hypothesize that replacing a stretch of sequence of an unstructured peptide motif with d-amino acids would increase its proteolytic stability without significantly affecting its affinity to the target protein. Also, considering the Cβ-Cβ distances, replacing an appropriate pair of residues with cysteine to form an additional disulfide bond in the molecule would provide additional stability to the engineered peptide. To verify this hypothesis, we have implemented these strategies to a previously reported peptidic inhibitor RR, against P. falciparum invasion into red blood cells (RBCs) and designed two novel heterochiral chimeric peptides, RR-I and RR-II. We have demonstrated that these peptides exhibit remarkable inhibitory activity with dramatically enhanced proteolytic stability. Finally, we have designed a cyclic analog, RR-III, to enhance the stability of the peptide against endopeptidases. The RR-III peptide exhibits the same inhibitory activity as RR-II while demonstrating impressive resistance to enzymatic degradation and prolonged stability in human plasma. These developments hold promise for a new generation of peptide-based therapeutics, showcasing the potential of residue selection for tailored modifications, as demonstrated in this work.

Mechanism of inhibiting periodontitis pathogenesis with various variations of inhibitors on Porphyromonas gingivalis: Systematic literature review

Background: Periodontal disease is the most prevalent disease worldwide with a prevalence of 20% to 50%, including periodontitis. Periodontitis involves complex interactions between specific pathogenic bacteria and host immune response. Microbial infections in subgingival biofilms are mainly caused by gram-negative bacteria including Porphyromonas gingivalis. Inhibition of Porphyromonas gingivalis virulence is one way to prevent periodontitis. This inhibition can be done in several ways through peptide inhibitors, quorum sensing inhibitors and natural inhibitors. Objective: This study aims to explain the mechanism of inhibiting periodontitis pathogenesis with various inhibitors on Porphyromonas gingivalis. Methods: his study employed a systematic literature review design by searching for articles based on predetermined inclusion and exclusion criteria. The search strategy used keywords and Boolean Operators from two databases (EBSCO and ProQuest). Results: he use of SAPP as a peptide inhibitor can inhibit the activity of Porphyromonas gingivalis gingipains, suppressing cytokine levels and inhibit colonization of Porphyromonas gingivalis. The use of furanone, D-ribose and BMK-Q101 as quorum sensing inhibitors can reduce Porphyromonas gingivalis in biofilms, inhibit the biosynthesis of autoinducer-2 so as to suppress the virulence factors of Porphyromonas gingivalis. The use of prenyl flavonoid as a natural inhibitor is a potent inhibitor of Arg-gingipain (Rgp) and Lys-gingipain (Kgp) and completely suppress the growth of Porphyromonas gingivalis. Conclusion: Inhibition of Porphyromonas gingivalis using peptide inhibitor, quorum sensing inhibitors and natural inhibitor can suppress virulence factors and inhibit biofilm formation of Porphyromonas gingivalis thus inhibiting the pathogenesis of periodontitis.

Virtual screening and evaluation of bioactive peptides from Haliotis discus hannai as potential HMGCR inhibitors for hyperlipidemia treatment.

Hyperlipidemia remains a major disease threatening global public health. The morbidity and mortality associated with cardiovascular diseases have been increasing. The inhibition of 3-Hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), a key enzyme in the cholesterol synthesis pathway, can effectively reduce cholesterol levels. In this study, the most suitable protease for preparing HMGCR inhibitory peptides was screened using the evaluation indexes of peptide yield and HMGCR inhibition rate. Peptide sequences with molecular weights <1 kDa were identified, and peptide fragments were docked with HMGCR for virtual screening. The inhibitory effects of these peptides on HMGCR activity were evaluated in vitro using a high-fat Hep-G2 cell model. The screened peptides possessed significant HMGCR inhibitory activity and reduced cholesterol micelle solubility and total cholesterol and triglyceride levels in hyperlipidemic Hep-G2 cells. This study provides novel insights into developing natural drugs for hyperlipidemia; moreover, the results will facilitate the functional application of marine bioactive peptides.

Peptide Profile Changes in Buffalo Milk Cheese during Different Storage Periods and Characterization of Novel Bioactive Peptides through Peptidomics.

This study aimed to investigate the changes in the bioactive peptides (BPs) of buffalo milk cheese (BMC) within 15 days of storage. A total of 3605 peptides were identified in the BMC, with 260 peptides remaining stable for 15 days. Among these, the peak intensities of all reported BPs (9 peptides) increased on the 15th day. Additionally, two novel antioxidant peptides, AYF (IC50 = 160.5 μM) and YPFPGPIPK (IC50 = 108.6 μM), and two novel angiotensin-converting enzyme (ACE) inhibitory peptides, LRF (IC50 = 214.9 μM) and APFPEVFGK (IC50 = 880.0 μM), were identified. The molecular docking results implied that the active sites on ECH-associated protein 1 (Arg 415, Arg 483, Arg 380, and Asn 382) and the active sites in the three active pockets of ACE (S1, S2, and S'1) are crucial for peptide activity. This study demonstrates that BMC is a stable resource of BPs and has the potential to be used in functional foods.

Research Progress of Food-Derived Antihypertensive Peptides in Regulating the Key Factors of the Renin-Angiotensin System.

Food protein-derived antihypertensive peptides have attracted substantial attention as a safer alternative for drugs. The regulation of the renin-angiotensin system (RAS) is an essential aspect underlying the mechanisms of antihypertensive peptides. Most of the identified antihypertensive peptides exhibit the angiotensin-converting enzyme (ACE) inhibitory effect. In addition, artificial intelligence has improved the efficiency of ACE inhibitory peptide identifications. Moreover, the inhibition of renin and blockade or down-regulation of angiotensin type I receptor (AT1R) have also been demonstrated to be effective intervention strategies. With the identification of the ACE2/Ang (1-7)/MasR axis, activation or up-regulation of angiotensin-converting enzyme 2 (ACE2) has also emerged as a new intervention pathway. This review summarizes the research progress of antihypertensive peptides in intervening with hypertension from the perspective of their properties, sources, and key factors. The objective of this review is to provide theoretical references for the development of antihypertensive peptides and the explorations of the molecular mechanisms.