RESUMEN
Type 2 diabetes is a chronic metabolic disorder characterized by high blood glucose levels due to either insufficient insulin production or ineffective utilization of insulin by the body. The enzyme dipeptidyl peptidase IV (DPP IV) plays a crucial role in degrading incretins that stimulate insulin secretion. Therefore, the inhibition of DPP IV is an established approach for the treatment of diabetes. Hemorphins are a class of short endogenous bioactive peptides produced by the enzymatic degradation of hemoglobin chains. Numerous in vitro and in vivo physiological effects of hemorphins, including DPP IV inhibiting activity, have been documented in different systems and tissues. However, the underlying molecular binding behavior of these peptides with DPP IV remains unknown. Here, computational approaches such as protein-peptide molecular docking and extensive molecular dynamics (MD) simulations were employed to identify the binding pose and stability of peptides in the active site of DPP IV. Findings indicate that hemorphins lacking the hydrophobic residues LVV and VV at the N terminal region strongly bind to the conserved residues in the active site of DPP IV. Furthermore, interactions with these critical residues were sustained throughout the duration of multiple 500 ns MD simulations. Notably, hemorphin 7 showed higher binding affinity and sustained interactions by binding to S1 and S2 pockets of DPP IV.
Asunto(s)
Diabetes Mellitus Tipo 2 , Inhibidores de la Dipeptidil-Peptidasa IV , Humanos , Inhibidores de la Dipeptidil-Peptidasa IV/farmacología , Simulación del Acoplamiento Molecular , Dipeptidil Peptidasa 4/metabolismo , Péptidos/química , Insulina , Simulación de Dinámica MolecularRESUMEN
Mcl-1 (myeloid cell leukemia 1), a member of the Bcl-2 family, is upregulated in various types of cancer. Peptides representing the BH3 (Bcl-2 homology 3) region of pro-apoptotic proteins have been demonstrated to bind the hydrophobic groove of anti-apoptotic Mcl-1, and this interaction is responsible for regulating apoptosis. Structural studies have shown that, while there is high overall structural conservation among the anti-apoptotic Bcl-2 (B-cell lymphoma 2) proteins, differences in the surface groove of these proteins facilitates binding specificity. This binding specificity is crucial for the mechanism of action of the Bcl-2 family in regulating apoptosis. Bim-based peptides bind specifically to the hydrophobic groove of Mcl-1, emphasizing the importance of these interactions in the regulation of cell death. Molecular docking was performed with BH3-like peptides derived from Bim to identify high affinity peptides that bind to Mcl-1 and to understand the molecular mechanism of their interactions. The interactions of three identified peptides, E2gY, E2gI, and XXA1_F3dI, were further evaluated using 250 ns molecular dynamics simulations. Conserved hydrophobic residues of the peptides play an important role in their binding and the structural stability of the complexes. Understanding the molecular basis of interaction of these peptides will assist in the development of more effective Mcl-1 specific inhibitors.
Asunto(s)
Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Proteína 1 de la Secuencia de Leucemia de Células Mieloides , Péptidos , Unión Proteica , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/metabolismo , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/química , Humanos , Péptidos/química , Péptidos/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacología , Antineoplásicos/metabolismo , Interacciones Hidrofóbicas e Hidrofílicas , Sitios de Unión , Secuencia de Aminoácidos , Proteína 11 Similar a Bcl2/metabolismo , Proteína 11 Similar a Bcl2/químicaRESUMEN
The most significant serotype of Shiga-toxigenic Escherichia coli that causes foodborne illnesses is Escherichia coli O157:H7. Elimination of E. coli O157:H7 during food processing and storage is a possible solution. Bacteriophages have a significant impact on bacterial populations in nature due to their ability to lyse their bacterial host. In the current study, a virulent bacteriophage, Ec_MI-02, was isolated from the feces of a wild pigeon in the United Arab Emirates (UAE) for potential future use as a bio-preservative or in phage therapy. Using a spot test and an efficiency of plating analysis, Ec_MI-02 was found to infect in addition to the propagation host, E. coli O157:H7 NCTC 12900, five different serotypes of E. coli O157:H7 (three clinical samples from infected patients, one from contaminated green salad, and one from contaminated ground beef). Based on morphology and genome analysis, Ec_MI-02 belongs to the genus Tequatrovirus under the order Caudovirales. The adsorption rate constant (K) of Ec_MI-02 was found to be 1.55 × 10-8 mL/min. The latent period was 50 min with a burst size of almost 10 plaque forming units (pfu)/host cell in the one-step growth curve when the phage Ec_MI-02 was cultivated using the propagation host E. coli O157:H7 NCTC 12900. Ec_MI-02 was found to be stable at a wide range of pH, temperature, and commonly used laboratory disinfectants. Its genome is 165,454 bp long with a GC content of 35.5% and encodes 266 protein coding genes. Ec_MI-02 has genes encoding for rI, rII, and rIII lysis inhibition proteins, which supports the observation of delayed lysis in the one-step growth curve. The current study provides additional evidence that wild birds could also be a good natural reservoir for bacteriophages that do not carry antibiotic resistance genes and could be good candidates for phage therapy. In addition, studying the genetic makeup of bacteriophages that infect human pathogens is crucial for ensuring their safe usage in the food industry.
Asunto(s)
Bacteriófagos , Escherichia coli O157 , Animales , Bovinos , Humanos , Escherichia coli O157/genética , Escherichia coli O157/metabolismo , Columbidae , Myoviridae/genética , Bacteriófagos/genética , Genómica , HecesRESUMEN
Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by elevated levels of blood glucose due to insulin resistance or insulin-secretion defects. The development of diabetes is mainly attributed to the interaction of several complex pathogenic, genetic, environmental and metabolic processes. Dipeptidyl peptidase-4 (DPP-4) is a serine protease that cleaves X-proline dipeptides from the N-terminus of several polypeptides, including natural hypoglycemic incretin hormones. Inhibition of this enzyme restores and maintains glucose homeostasis, making it an attractive drug target for the management of T2DM. Natural products are important sources of bioactive agents for anti-T2DM drug discovery. Marine ecosystems are a rich source of bioactive products and have inspired the development of drugs for various human disorders, including diabetes. Here, structure-based virtual screening and molecular docking were performed to identify antidiabetic compounds from the Comprehensive Marine Natural Products Database (CMNPD). The binding characteristics of two shortlisted compounds, CMNPD13046 and CMNPD17868, were assessed using molecular dynamics simulations. Thus, this study provides insights into the potential antidiabetic activity and the underlying molecular mechanism of two compounds of marine origin. These compounds could be investigated further for the development of potent DPP-4 inhibitors.
Asunto(s)
Productos Biológicos , Bases de Datos Farmacéuticas , Inhibidores de la Dipeptidil-Peptidasa IV , Hipoglucemiantes , Humanos , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Inhibidores de la Dipeptidil-Peptidasa IV/química , Inhibidores de la Dipeptidil-Peptidasa IV/farmacología , Ecosistema , Hipoglucemiantes/química , Hipoglucemiantes/farmacología , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Productos Biológicos/química , Productos Biológicos/farmacología , Relación Estructura-Actividad , Evaluación Preclínica de MedicamentosRESUMEN
Verotoxin-producing Escherichia coli O157:H7 is responsible for the majority of foodborne outbreaks worldwide and may lead to death. Bacteriophages are natural killers of bacteria. All previously reported E. coli O157:H7 phages were isolated from ruminants or swine. Here, we report for the first time a phage isolated from bird feces in the United Arab Emirates (UAE), designated as UAE_MI-01, indicating birds as a good source of phages. Thus, phages could be a tool for predicting the presence of the host bacteria in an animal or the environment. UAE_MI-01 was found to be a lytic phage that was stable at wide ranges of pH, temperature, and chemical disinfectants, and with a burst size of almost 100 plaque-forming units per host cell after a latent period of 20 min and an adsorption rate constant (K) of 1.25 × 10-7 mL min-1. The phage genome was found to be 44,281 bp long with an average GC content of 54.7%. The presence of the phage indicates the presence of the host cell E. coli O157:H7 in wild birds. Therefore, other birds, mainly poultry, could be also investigated for the presence of this pathogenic bacterium. To the best of our knowledge, this is the first report of an E. coli O157:H7 bacteriophage isolated from a bird.
Asunto(s)
Bacteriófagos , Escherichia coli O157 , Animales , Porcinos , Escherichia coli O157/genética , Bacteriófagos/genética , Emiratos Árabes Unidos , Genoma , Genómica , RumiantesRESUMEN
We predicted water-octanol partition coefficients for the molecules in the SAMPL7 challenge with explicit solvent classical molecular dynamics (MD) simulations. Water hydration free energies and octanol solvation free energies were calculated with a windowed alchemical free energy approach. Three commonly used force fields (AMBER GAFF, CHARMM CGenFF, OPLS-AA) were tested. Special emphasis was placed on converging all simulations, using a criterion developed for the SAMPL6 challenge. In aggregate, over 1000 [Formula: see text]s of simulations were performed, with some free energy windows remaining not fully converged even after 1 [Formula: see text]s of simulation time. Nevertheless, the amount of sampling produced [Formula: see text] estimates with a precision of 0.1 log units or better for converged simulations. Despite being probably as fully sampled as can expected and is feasible, the agreement with experiment remained modest for all force fields, with no force field performing better than 1.6 in root mean squared error. Overall, our results indicate that a large amount of sampling is necessary to produce precise [Formula: see text] predictions for the SAMPL7 compounds and that high precision does not necessarily lead to high accuracy. Thus, fundamental problems remain to be solved for physics-based [Formula: see text] predictions.
Asunto(s)
Octanoles/química , Proteínas/química , Programas Informáticos , Agua/química , Entropía , Ligandos , Modelos Químicos , Simulación de Dinámica Molecular , Solventes/química , TermodinámicaRESUMEN
Novel antihypercholesterolemic bioactive peptides (BAP) from peptic camel whey protein hydrolysates (CWPH) were generated at different time, temperature, and enzyme concentration (%). Hydrolysates showed higher pancreatic lipase- (PL; except 3 CWPH) and cholesterol esterase (CE)-inhibiting potential, as depicted by lower half-maximal inhibitory concentration values (IC50 values) compared with nonhydrolyzed camel whey proteins (CWP). Peptide sequencing and in silico data depicted that most BAP from CWPH could bind active site of PL, whereas as only 3 peptides could bind the active site of CE. Based on higher number of reactive residues in the BAP and greater number of substrate binding sites, FCCLGPVPP was identified as a potential CE-inhibitory peptide, and PAGNFLPPVAAAPVM, MLPLMLPFTMGY, and LRFPL were identified as PL inhibitors. Molecular docking of selected peptides showed hydrophilic and hydrophobic interactions between peptides and target enzymes. Thus, peptides derived from CWPH warrant further investigation as potential candidates for adjunct therapy for hypercholesterolemia.
Asunto(s)
Camelus , Esterol Esterasa , Animales , Lipasa , Simulación del Acoplamiento Molecular , Péptidos , Hidrolisados de Proteína , Suero Lácteo , Proteína de Suero de LecheRESUMEN
Diabetes mellitus is a major public health concern associated with high mortality and reduced life expectancy. The alarming rise in the prevalence of diabetes is linked to several factors including sedentary lifestyle and unhealthy diet. Nutritional intervention and increased physical activity could significantly contribute to bringing this under control. Food-derived bioactive peptides and protein hydrolysates have been associated with a number health benefits. Several peptides with antidiabetic potential have been identified that could decrease blood glucose level, improve insulin uptake and inhibit key enzymes involved in the development and progression of diabetes. Dietary proteins, from a wide range of food, are rich sources of antidiabetic peptides. Thus, there are a number of benefits in studying peptides obtained from food sources to develop nutraceuticals. A deeper understanding of the underlying molecular mechanisms of these peptides will assist in the development of new peptide-based therapeutics. Despite this, a comprehensive analysis of the antidiabetic properties of bioactive peptides derived from various food sources is still lacking. Here, we review the recent literature on food-derived bioactive peptides possessing antidiabetic activity. The focus is on the effectiveness of these peptides as evidenced by in vitro and in vivo studies. Finally, we discuss future prospects of peptide-based drugs for the treatment of diabetes.
Asunto(s)
Diabetes Mellitus/dietoterapia , Suplementos Dietéticos , Alimentos Funcionales , Hipoglucemiantes/análisis , Péptidos/uso terapéutico , Humanos , Péptidos/químicaRESUMEN
Human α-defensin 5 (HD5) is a host-defense peptide exhibiting broad-spectrum antimicrobial activity. The lipopolysaccharide (LPS) layer on the Gram-negative bacterial membrane acts as a barrier to HD5 insertion. Therefore, the pore formation and binding mechanism remain unclear. Here, the binding mechanisms at five positions along the bacterial membrane axis were investigated using Molecular Dynamics. (MD) simulations. We found that HD5 initially placed at positions 1 to 3 moved up to the surface, while HD5 positioned at 4 and 5 remained within the membrane interacting with the middle and inner leaflet of the membrane, respectively. The arginines were key components for tighter binding with 3-deoxy-d-manno-octulosonic acid (KDO), phosphates of the outer and inner leaflets. KDO appeared to retard the HD5 penetration.
Asunto(s)
Antiinfecciosos/metabolismo , Membrana Celular/metabolismo , Bacterias Gramnegativas/metabolismo , Simulación de Dinámica Molecular , alfa-Defensinas/metabolismo , Secuencia de Aminoácidos , Antiinfecciosos/química , Arginina/metabolismo , Humanos , Enlace de Hidrógeno , Lipopolisacáridos/metabolismo , Unión Proteica , Multimerización de Proteína , Azúcares Ácidos/metabolismo , alfa-Defensinas/químicaRESUMEN
The accumulation of toxic chemical constituents in sludge and wastewater has fuelled an interest in investigating efficient and eco-friendly wastewater remediation approaches. In this study, a set of bacterial samples were isolated from petroleum sludge and tested for their ability to degrade different aromatic pollutants, including azo dyes and emerging pollutants. Although exhibiting differential specificity, all bacterial isolates were able to degrade different classes of aromatic dyes efficiently. Ribosomal 16S rRNA sequencing of the 12 bacterial isolates showed that they belonged to two different bacterial genera: Bacillus cereus and Pseudomonas guariconensis. Of these 12 strains, MA1 (B. cereus) was the most promising and was chosen for further optimization and biochemical studies. The optimum culture and remediation conditions for MA1 was found to be at pH 7, with 100 ppm dye concentration, and under aerobic condition. In addition to efficiently degrading various aromatic dyes (e.g. Congo Red, Reactive Black 5, PBS, and Toluidine Blue), MA1 was also found to be capable of degrading various emerging pollutants (e.g. prometryn, fluometuron and sulfamethoxazole). Preliminary transcriptome analysis shows that MA1 grown on media containing a mixture of aromatic dyes appears to differentially express a number of genes. Data shown here strongly suggests that petroleum sludge is a rich reservoir of bacteria with powerful remediation abilities.
Asunto(s)
Bacillus , Contaminantes Ambientales , Petróleo , Bacillus cereus/genética , Biodegradación Ambiental , Pseudomonas , ARN Ribosómico 16S/genética , Aguas del AlcantarilladoRESUMEN
Hemorphins are endogenous peptides, 4-10 amino acids long, belonging to the family of atypical opioid peptides released during the sequential cleavage of hemoglobin protein. Hemorphins have been shown to exhibit diverse therapeutic effects in both human and animal models. However, the precise cellular and molecular mechanisms involved in such effects remain elusive. In this review, we summarize and propose potential mechanisms based on studies that investigated the biological activity of hemorphins of different lengths on multiple therapeutic targets. Special emphasis is given to molecular events related to renin-angiotensin system (RAS), opioid receptors and insulin-regulated aminopeptidase receptor (IRAP). This review provides a comprehensive coverage of the molecular mechanisms that underpin the therapeutic potential of hemorphins. Furthermore, it highlights the role of various hemorphin residues in pathological conditions, which could be explored further for therapeutic purposes.
Asunto(s)
Péptidos Opioides/fisiología , Péptidos Opioides/uso terapéutico , Animales , Humanos , Proteína Antagonista del Receptor de Interleucina 1/efectos de los fármacos , Neoplasias/tratamiento farmacológico , Péptidos Opioides/química , Receptores Opioides/efectos de los fármacos , Sistema Renina-Angiotensina/efectos de los fármacosRESUMEN
Hemorphins are known for their role in the control of blood pressure. Recently, we revealed the positive modulation of the angiotensin II (AngII) type 1 receptor (AT1R) by LVV-hemorphin-7 (LVV-H7) in human embryonic kidney (HEK293) cells. Here, we examined the molecular binding behavior of LVV-H7 on AT1R and its effect on AngII binding using a nanoluciferase-based bioluminescence resonance energy transfer (NanoBRET) assay in HEK293FT cells, as well as molecular docking and molecular dynamics (MD) studies. Saturation and real-time kinetics supported the positive effect of LVV-H7 on the binding of AngII. While the competitive antagonist olmesartan competed with AngII binding, LVV-H7 slightly, but significantly, decreased AngII's kD by 2.6 fold with no effect on its Bmax. Molecular docking and MD simulations indicated that the binding of LVV-H7 in the intracellular region of AT1R allosterically potentiates AngII binding. LVV-H7 targets residues on intracellular loops 2 and 3 of AT1R, which are known binding sites of allosteric modulators in other GPCRs. Our data demonstrate the allosteric effect of LVV-H7 on AngII binding, which is consistent with the positive modulation of AT1R activity and signaling previously reported. This further supports the pharmacological targeting of AT1R by hemorphins, with implications in vascular and renal physiology.
Asunto(s)
Angiotensina II/metabolismo , Hemoglobinas/metabolismo , Fragmentos de Péptidos/metabolismo , Receptor de Angiotensina Tipo 1/metabolismo , Células HEK293 , Humanos , Simulación del Acoplamiento Molecular , Simulación de Dinámica MolecularRESUMEN
Novel bioactive peptides from camel milk protein hydrolysates (CMPH) were identified and tested for inhibition of cholesterol esterase (CEase), and their possible binding mechanisms were elucidated by molecular docking. Papain-generated CMPH showed the highest degree of hydrolysis. All CMPH produced upon enzymatic degradation demonstrated a dramatic enhancement of CEase inhibition compared with intact camel milk proteins, with papain-generated hydrolysate P9 displaying the highest inhibition. Peptide identification and their modeling through PepSite 2 revealed that among 20 potential bioactive peptides in alcalase-generated hydrolysate A9, only 3 peptides, with sequences KFQWGY, SQDWSFY, and YWYPPQ, showed the highest binding toward CEase catalytic sites. Among 43 peptides in 9-h papain-generated hydrolysate P9, 4 peptides were found to be potent CEase inhibitors. Molecular docking revealed that WPMLQPKVM, CLSPLQMR, MYQQWKFL, and CLSPLQFR from P9 hydrolysates were able to bind to the active site of CEase with good docking scores and molecular mechanics-generalized born surface area binding energies. Overall, this is the first study reporting CEase inhibitory potential of peptides generated from milk proteins.
Asunto(s)
Camelus , Inhibidores Enzimáticos/aislamiento & purificación , Proteínas de la Leche/química , Péptidos/química , Esterol Esterasa/antagonistas & inhibidores , Animales , Camelus/metabolismo , Inhibidores Enzimáticos/química , Femenino , Leche/química , Simulación del Acoplamiento Molecular , Papaína/química , Péptidos/aislamiento & purificación , Hidrolisados de Proteína/química , Subtilisinas/químicaRESUMEN
BACKGROUND: Congenital hydrocephalus (CH) results from the accumulation of excessive amounts of cerebrospinal fluid (CSF) in the brain, often leading to severe neurological impairments. However, the adverse effects of CH can be reduced if the condition is detected and treated early. Earlier reports demonstrated that some CH cases are caused by mutations in L1CAM gene encoding the neural cell adhesion molecule L1. On the other hand, recent studies have implicated the multiple PDZ domain (MPDZ) gene in some severe forms of CH, inherited in an autosomal recessive pattern. METHODS: In this study, whole-exome and Sanger sequencing were performed on a 9 months old Emirati child clinically diagnosed by CH. In addition, in silico, cellular, and molecular assays have been conducted to confirm pathogenicity of the identified variants and to establish disease mechanism. RESULTS: Whole exome sequencing revealed two compound heterozygous novel variants (c.394G > A and c.1744C > G) in the affected child within the MPDZ gene. Segregation analysis revealed that each of the parents is heterozygous for one of the two variants and therefore passed that variant to their child. The outcome of the in silico and bioinformatics analyses came in line with the experimental data, suggesting that the two variants are most likely disease causing. CONCLUSIONS: The compound heterozygous variants identified in this study are the most likely cause of CH in the affected child. The study further confirms MPDZ as a gene underlying some CH cases.
Asunto(s)
Heterocigoto , Hidrocefalia/diagnóstico por imagen , Hidrocefalia/genética , Molécula L1 de Adhesión de Célula Nerviosa/genética , Dominios PDZ/genética , Secuencia de Aminoácidos , Encéfalo/metabolismo , Adhesión Celular , Genes Recesivos , Variación Genética , Células HEK293 , Células HeLa , Humanos , Lactante , Masculino , Mutación , Neuronas/citología , Neuronas/efectos de los fármacos , Linaje , Conformación Proteica , Análisis de Secuencia de ADN , Secuenciación del ExomaRESUMEN
The enduring relationship between dietary patterns and human health has led us to investigate the bioactive components present in fruits and vegetables for a very long time. Berries, notably the popular ones such as strawberry, raspberry, blueberry, blackberry, and the Indian gooseberry, are among the best known dietary sources due to the presence of a wide range of bioactive nutritive components. Bioactive components in berries include phenolic compounds, flavonoids, and tannins apart from vitamins, minerals, sugars, and fibers. Individually or synergistically, these have been shown to provide protection against several disorders. Mounting evidence suggests that consumption of berries confer antioxidant and anticancer protection to humans and animals. Free radical scavenging, protection from DNA damage, induction of apoptosis, and inhibition of growth and proliferation of cancer cells are just to name a few. This review comprehensively summarizes the key phytochemicals present in berries and their biological action in preventing oxidative stress and carcinogenesis.
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Antineoplásicos/química , Antineoplásicos/farmacología , Antioxidantes/química , Antioxidantes/farmacología , Frutas/química , Animales , Humanos , Neoplasias/tratamiento farmacológico , Fitoquímicos/química , Fitoquímicos/farmacología , FitoterapiaRESUMEN
The α4ß2 nicotinic acetylcholine receptor (nAChR) is the most abundant nAChR type in the brain, and this receptor type exists in alternate (α4ß2)2α4 and (α4ß2)2ß2 forms, which are activated by agonists with strikingly differing efficacies. Recent breakthroughs have identified an additional operational agonist binding site in the (α4ß2)2α4 nAChR that is responsible for the signature sensitivity of this receptor to activation by agonists, yet the structural mechanisms determining agonist efficacy at this receptor type are not yet fully understood. In this study, we characterized the ligand selectivity of the individual agonist sites of the (α4ß2)2α4 nAChR to determine whether differences in agonist selectivity influence agonist efficacy. Applying the substituted cysteine accessibility method to individual agonist sites in concatenated (α4ß2)2α4 receptors, we determined the agonist selectivity of the agonist sites of the (α4ß2)2α4 receptor. We show that (a) accessibility of substituted cysteines to covalent modification by methanesulfonate reagent depends on the agonist site at which the modification occurs and (b) that agonists such as sazetidine-A and TC-2559 are excluded from the site at the α4/α4 interface. Given that additional binding to the agonist site in the α4/α4 interface increases acetylcholine efficacy and that agonists excluded from the agonist site at the α4/α4 interface behave as partial agonists, we conclude that the ability to engage all agonist sites in (α4ß2)2α4 nAChRs is a key determinant of agonist efficacy. The findings add another level of complexity to the structural mechanisms that govern agonist efficacy in heteromeric nAChRs and related ligand-gated ion channels.
Asunto(s)
Agonistas Nicotínicos/farmacología , Receptores Nicotínicos/metabolismo , Animales , Ligandos , Receptores Nicotínicos/genética , Xenopus laevisRESUMEN
G protein-coupled receptors (GPCRs) make up the largest receptor superfamily, accounting for 4% of protein-coding genes. Despite the prevalence of such transmembrane receptors, a significant number remain orphans, lacking identified endogenous ligands. Since their conception, the reverse pharmacology approach has been used to characterize such receptors. However, the multifaceted and nuanced nature of GPCR signaling poses a great challenge to their pharmacological elucidation. Considering their therapeutic relevance, the search for native orphan GPCR ligands continues. Despite limited structural input in terms of 3D crystallized structures, with advances in machine-learning approaches, there has been great progress with respect to accurate ligand prediction. Though such an approach proves valuable given that ligand scarcity is the greatest hurdle to orphan GPCR deorphanization, the future pairings of the remaining orphan GPCRs may not necessarily take a one-size-fits-all approach but should be more comprehensive in accounting for numerous nuanced possibilities to cover the full spectrum of GPCR signaling.
RESUMEN
Hemorphins, short bioactive peptides produced by enzymatic cleavage of ß-hemoglobin, exhibit antihypertensive properties by inhibiting angiotensin-1 converting enzyme (ACE1). ACE1 is a key player in the renin-angiotensin system (RAS) and regulates blood pressure. ACE1 and its homolog, ACE2, which exhibit opposing activities in the RAS, share considerable similarity in their catalytic domains. The primary objective of this study was to identify and contrast the molecular mechanisms underlying the interaction of hemorphins of camels and that of other mammals with the two ACE homologs. In silico docking and molecular dynamics simulations were performed for ACE1 and ACE2, along with in vitro confirmatory assays for ACE1. The C-domain of ACE1, primarily involved in regulating blood pressure, was used along with the N-terminal peptidase domain of ACE2. The findings revealed conserved hemorphin interactions with equivalent regions of the two ACE homologs and differential residue-level interactions reflecting the substrate preferences of ACE1 and ACE2 considering their opposing functions. Therefore, conserved residue-level associations and implications of poorly conserved regions between the two ACE receptors may potentially guide the discovery of selective domain-specific inhibitors. The findings of this study can provide a basis for the treatment of related disorders in the future.
Asunto(s)
Enzima Convertidora de Angiotensina 2 , Peptidil-Dipeptidasa A , Animales , Sistema Renina-Angiotensina , Antihipertensivos , Presión Sanguínea , CamelusRESUMEN
Methylmalonic aciduria and homocystinuria type C protein (MMACHC) is required by the body to metabolize cobalamin (Cbl). Due to its complex structure and cofactor forms, Cbl passes through an extensive series of absorptive and processing steps before being delivered to mitochondrial methyl malonyl-CoA mutase and cytosolic methionine synthase. Depending on the cofactor attached, MMACHC performs either flavin-dependent reductive decyanation or glutathione (GSH)-dependent dealkylation. The alkyl groups of Cbl have to be removed in the presence of GSH to produce intermediates that can later be converted into active cofactor forms. Pathogenic mutations in the GSH binding site, such as R161Q, R161G, R206P, R206W, and R206Q, have been reported to cause Cbl diseases. The impact of these variations on MMACHC's structure and how it affects GSH and Cbl binding at the molecular level is poorly understood. To better understand the molecular basis of this interaction, mutant structures involving the MMACHC-MeCbl-GSH complex were generated using in silico site-directed point mutations and explored using molecular dynamics (MD) simulations. The results revealed that mutations in the key arginine residues disrupt GSH binding by breaking the interactions and reducing the free energy of binding of GSH. Specifically, variations at position 206 appeared to produce weaker GSH binding. The lowered binding affinity for GSH in the variant structures could impact metabolic pathways involving Cbl and its trafficking.
RESUMEN
Hypercholesterolemia remains a serious global public health concern. Previously, synthetic anti-hypercholesterolemic drugs were used for ameliorating this condition; however, long-term usage presented several side-effects. In this regard, natural products as an adjunct therapy has emerged in recent times. This study aimed to produce novel bioactive peptides with anti-hypercholesterolemic activity (cholesterol esterase (CEase) and pancreatic lipase (PL)) from quinoa protein hydrolysates (QPHs) using three enzymatic hydrolysis methods (chymotrypsin, protease and bromelain) at 2-h hydrolysis intervals (2, 4, and 6 h). Chymotrypsin-generated hydrolysates showed higher CEase (IC50: 0.51 mg/mL at 2 h) and PL (IC50: 0.78 mg/mL at 6 h) inhibitory potential in comparison to other derived hydrolysates and intact quinoa proteins. Peptide profiling by LC-MS QTOF and in silico interaction with target enzymes showed that only four derived bioactive peptides from QPHs could bind in the active site of CEase, whereas twelve peptides could bind in the active site of PL. Peptides QHPHGLGALCAAPPST, HVQGHPALPGVPAHW, and ASNLDNPSPEGTVM were identified to be potential CEase inhibitors, and FSAGGLP, QHPHGLGALCAAPPST, KIVLDSDDPLFGGF, MFVPVPH, and HVQGHPALPGVPAHW were identified as potential PL inhibitors on the basis of the maximum number of reactive residues in these bioactive peptides. In conclusion, QPHs can be considered as an alternative therapy for the treatment of hypercholesterolemia.