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1.
Int J Mol Sci ; 22(12)2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34203978

RESUMO

Alzheimer's disease (AD) is the major cause of dementia, and affected individuals suffer from severe cognitive, mental, and functional impairment. Histologically, AD brains are basically characterized by the presence of amyloid plaques and neurofibrillary tangles. Previous reports demonstrated that protein kinase CK1δ influences the metabolism of amyloid precursor protein (APP) by inducing the generation of amyloid-ß (Aß), finally contributing to the formation of amyloid plaques and neuronal cell death. We therefore considered CK1δ as a promising therapeutic target and suggested an innovative strategy for the treatment of AD based on peptide therapeutics specifically modulating the interaction between CK1δ and APP. Initially, CK1δ-derived peptides manipulating the interactions between CK1δ and APP695 were identified by interaction and phosphorylation analysis in vitro. Selected peptides subsequently proved their potential to penetrate cells without inducing cytotoxic effects. Finally, for at least two of the tested CK1δ-derived peptides, a reduction in Aß levels and amyloid plaque formation could be successfully demonstrated in a complex cell culture model for AD. Consequently, the presented results provide new insights into the interactions of CK1δ and APP695 while also serving as a promising starting point for further development of novel and highly innovative pharmacological tools for the treatment of AD.


Assuntos
Precursor de Proteína beta-Amiloide/metabolismo , Caseína Quinase Idelta/metabolismo , Peptídeos/metabolismo , Precursor de Proteína beta-Amiloide/química , Caseína Quinase Idelta/química , Morte Celular , Sobrevivência Celular , Humanos , Simulação de Acoplamento Molecular , Neurônios/metabolismo , Fosforilação , Placa Amiloide/metabolismo , Placa Amiloide/patologia , Ligação Proteica
2.
Molecules ; 26(12)2021 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-34204651

RESUMO

The driving forces and conformational pathways leading to amphitropic protein-membrane binding and in some cases also to protein misfolding and aggregation is the subject of intensive research. In this study, a chimeric polypeptide, A-Cage-C, derived from α-Lactalbumin is investigated with the aim of elucidating conformational changes promoting interaction with bilayers. From previous studies, it is known that A-Cage-C causes membrane leakages associated with the sporadic formation of amorphous aggregates on solid-supported bilayers. Here we express and purify double-labelled A-Cage-C and prepare partially deuterated bicelles as a membrane mimicking system. We investigate A-Cage-C in the presence and absence of these bicelles at non-binding (pH 7.0) and binding (pH 4.5) conditions. Using in silico analyses, NMR, conformational clustering, and Molecular Dynamics, we provide tentative insights into the conformations of bound and unbound A-Cage-C. The conformation of each state is dynamic and samples a large amount of overlapping conformational space. We identify one of the clusters as likely representing the binding conformation and conclude tentatively that the unfolding around the central W23 segment and its reorientation may be necessary for full intercalation at binding conditions (pH 4.5). We also see evidence for an overall elongation of A-Cage-C in the presence of model bilayers.


Assuntos
Proteína Oncogênica pp60(v-src)/química , Fragmentos de Peptídeos/química , Peptídeos/química , Lactalbumina/química , Espectroscopia de Ressonância Magnética/métodos , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Membranas , Simulação de Dinâmica Molecular , Proteína Oncogênica pp60(v-src)/metabolismo , Fragmentos de Peptídeos/metabolismo , Peptídeos/metabolismo , Ligação Proteica , Conformação Proteica
3.
Molecules ; 26(12)2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34207044

RESUMO

Among biological macromolecules, proteins hold prominent roles in a vast array of physiological and pathological processes [...].


Assuntos
Peptídeos/química , Peptídeos/metabolismo , Proteínas/química , Proteínas/metabolismo , Humanos , Conformação Proteica
4.
Molecules ; 26(12)2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34207274

RESUMO

The rate of successful identification of peptide sequences by tandem mass spectrometry (MS/MS) is adversely affected by the common occurrence of co-isolation and co-fragmentation of two or more isobaric or isomeric parent ions. This results in so-called `chimera spectra', which feature peaks of the fragment ions from more than a single precursor ion. The totality of the fragment ion peaks in chimera spectra cannot be assigned to a single peptide sequence, which contradicts a fundamental assumption of the standard automated MS/MS spectra analysis tools, such as protein database search engines. This calls for a diagnostic method able to identify chimera spectra to single out the cases where this assumption is not valid. Here, we demonstrate that, within the recently developed two-dimensional partial covariance mass spectrometry (2D-PC-MS), it is possible to reliably identify chimera spectra directly from the two-dimensional fragment ion spectrum, irrespective of whether the co-isolated peptide ions are isobaric up to a finite mass accuracy or isomeric. We introduce '3-57 chimera tag' technique for chimera spectrum diagnostics based on 2D-PC-MS and perform numerical simulations to examine its efficiency. We experimentally demonstrate the detection of a mixture of two isomeric parent ions, even under conditions when one isomeric peptide is at one five-hundredth of the molar concentration of the second isomer.


Assuntos
Quimera/metabolismo , Peptídeos/metabolismo , Espectrometria de Massas em Tandem/métodos , Bases de Dados de Proteínas , Íons/metabolismo , Proteômica/métodos
5.
Int J Mol Sci ; 22(11)2021 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-34204153

RESUMO

Chromogranin A (CgA), B (CgB), and C (CgC), the family members of the granin glycoproteins, are associated with diabetes. These proteins are abundantly expressed in neurons, endocrine, and neuroendocrine cells. They are also present in other areas of the body. Patients with diabetic retinopathy have higher levels of CgA, CgB, and CgC in the vitreous humor. In addition, type 1 diabetic patients have high CgA and low CgB levels in the circulating blood. Plasma CgA levels are increased in patients with hypertension, coronary heart disease, and heart failure. CgA is the precursor to several functional peptides, including catestatin, vasostatin-1, vasostatin-2, pancreastatin, chromofungin, and many others. Catestatin, vasostain-1, and vasostatin-2 suppress the expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 in human vascular endothelial cells. Catestatin and vasostatin-1 suppress oxidized low-density lipoprotein-induced foam cell formation in human macrophages. Catestatin and vasostatin-2, but not vasostatin-1, suppress the proliferation and these three peptides suppress the migration in human vascular smooth muscles. Chronic infusion of catestatin, vasostatin-1, or vasostatin-2 suppresses the development of atherosclerosis of the aorta in apolipoprotein E-deficient mice. Catestatin, vasostatin-1, vasostatin-2, and chromofungin protect ischemia/reperfusion-induced myocardial dysfunction in rats. Since pancreastatin inhibits insulin secretion from pancreatic ß-cells, and regulates glucose metabolism in liver and adipose tissues, pancreastatin inhibitor peptide-8 (PSTi8) improves insulin resistance and glucose homeostasis. Catestatin stimulates therapeutic angiogenesis in the mouse hind limb ischemia model. Gene therapy with secretoneurin, a CgC-derived peptide, stimulates postischemic neovascularization in apolipoprotein E-deficient mice and streptozotocin-induced diabetic mice, and improves diabetic neuropathy in db/db mice. Therefore, CgA is a biomarker for atherosclerosis, diabetes, hypertension, and coronary heart disease. CgA- and CgC--derived polypeptides provide the therapeutic target for atherosclerosis and ischemia-induced tissue damages. PSTi8 is useful in the treatment of diabetes.


Assuntos
Aterosclerose/metabolismo , Cromograninas/metabolismo , Doença das Coronárias/metabolismo , Diabetes Mellitus/metabolismo , Peptídeos/metabolismo , Animais , Biomarcadores/metabolismo , Humanos
6.
Molecules ; 26(11)2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34200462

RESUMO

Gastropods are among the most diverse animals. Gastropod mucus contains several glycoproteins and peptides that vary by species and habitat. Some bioactive peptides from gastropod mucus were identified only in a few species. Therefore, using biochemical, mass spectrometric, and bioinformatics approaches, this study aimed to comprehensively identify putative bioactive peptides from the mucus proteomes of seven commonly found or commercially valuable gastropods. The mucus was collected in triplicate samples, and the proteins were separated by 1D-SDS-PAGE before tryptic digestion and peptide identification by nano LC-MS/MS. The mucus peptides were subsequently compared with R scripts. A total of 2818 different peptides constituting 1634 proteins from the mucus samples were identified, and 1218 of these peptides (43%) were core peptides found in the mucus of all examined species. Clustering and correspondence analyses of 1600 variable peptides showed unique mucous peptide patterns for each species. The high-throughput k-nearest neighbor and random forest-based prediction programs were developed with more than 95% averaged accuracy and could identify 11 functional categories of putative bioactive peptides and 268 peptides (9.5%) with at least five to seven bioactive properties. Antihypertensive, drug-delivering, and antiparasitic peptides were predominant. These peptides provide an understanding of gastropod mucus, and the putative bioactive peptides are expected to be experimentally validated for further medical, pharmaceutical, and cosmetic applications.


Assuntos
Gastrópodes/metabolismo , Muco/metabolismo , Peptídeos/metabolismo , Proteoma/metabolismo , Animais , Cromatografia Líquida/métodos , Biologia Computacional/métodos , Eletroforese em Gel de Poliacrilamida/métodos , Aprendizado de Máquina , Proteômica/métodos , Espectrometria de Massas em Tandem/métodos
7.
Sheng Wu Gong Cheng Xue Bao ; 37(6): 2166-2180, 2021 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-34227301

RESUMO

Bioactive peptides play important roles in promoting human health, such as lowering blood pressure, blood sugar and blood lipid, anti-obesity, and anti-cancer. Thus, exploring functional bioactive peptides and developing efficient production technologies are of crucial importance. Herein, we review the development of function discovery and production technology for natural bioactive peptides. Presently, the top-down and bottom-up approaches are mainly used for the function discovery and production of natural active peptides. The top-down approach includes the direct extraction and identification for functional discovery, and the direct extraction, enzymatic hydrolysis and microbial fermentation for production. The bottom-up approach includes the polypeptide modification and database mining for functional discovery, and the chemical synthesis, enzyme synthesis, recombinant expression and cell-free synthesis for production. The top-down approach is usually associated with complicated process, lower efficiency, higher cost, harder quality control, and uncertain functionality, while the bottom-up approach is more suitable for the development of peptide drugs but difficult to be used for functional foods. With the technology development of sequencing and mass spectrometry, it is easier to obtain the proteomic information of various organisms at the molecular level. Based on the proteomic information, the top-down and bottom-up approaches can be combined to overcome the disadvantages of using these two approaches alone, thus providing a new strategy for the rapid development and production of natural active peptides.


Assuntos
Peptídeos , Proteômica , Fermentação , Humanos , Espectrometria de Massas , Peptídeos/metabolismo , Tecnologia
8.
Nat Commun ; 12(1): 3412, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34099696

RESUMO

De novo designed self-assembling peptides (SAPs) are promising building blocks of supramolecular biomaterials, which can fulfill a wide range of applications, such as scaffolds for tissue culture, three-dimensional cell culture, and vaccine adjuvants. Nevertheless, the use of SAPs in intracellular spaces has mostly been unexplored. Here, we report a self-assembling peptide, Y15 (YEYKYEYKYEYKYEY), which readily forms ß-sheet structures to facilitate bottom-up synthesis of functional protein assemblies in living cells. Superfolder green fluorescent protein (sfGFP) fused to Y15 assembles into fibrils and is observed as fluorescent puncta in mammalian cells. Y15 self-assembly is validated by fluorescence anisotropy and pull-down assays. By using the Y15 platform, we demonstrate intracellular reconstitution of Nck assembly, a Src-homology 2 and 3 domain-containing adaptor protein. The artificial clusters of Nck induce N-WASP (neural Wiskott-Aldrich syndrome protein)-mediated actin polymerization, and the functional importance of Nck domain valency and density is evaluated.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Materiais Biocompatíveis/metabolismo , Proteínas Oncogênicas/metabolismo , Peptídeos/metabolismo , Actinas/metabolismo , Animais , Materiais Biocompatíveis/química , Células COS , Chlorocebus aethiops , Células HEK293 , Humanos , Biossíntese de Peptídeos Independentes de Ácido Nucleico , Peptídeos/química , Conformação Proteica em Folha beta , Domínios Proteicos , Multimerização Proteica , Proteína Neuronal da Síndrome de Wiskott-Aldrich/metabolismo
9.
J Phys Chem B ; 125(24): 6572-6586, 2021 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-34114829

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has evolved into a pandemic of unprecedented scale. This coronavirus enters cells by the interaction of the receptor binding domain (RBD) with the human angiotensin-converting enzyme 2 receptor (hACE2). In this study, we employed a rational structure-based design to propose 22-mer stapled peptides using the structure of the hACE2 α1 helix as a template. These peptides were designed to retain the α-helical character of the natural structure, to enhance binding affinity, and to display a better solubility profile compared to other designed peptides available in the literature. We employed different docking strategies (PATCHDOCK and ZDOCK) followed by a double-step refinement process (FIBERDOCK) to rank our peptides, followed by stability analysis/evaluation of the interaction profile of the best docking predictions using a 500 ns molecular dynamics (MD) simulation, and a further binding affinity analysis by molecular mechanics with generalized Born and surface area (MM/GBSA) method. Our most promising stapled peptides presented a stable profile and could retain important interactions with the RBD in the presence of the E484K RBD mutation. We predict that these peptides can bind to the viral RBD with similar potency to the control NYBSP-4 (a 30-mer experimentally proven peptide inhibitor). Furthermore, our study provides valuable information for the rational design of double-stapled peptide as inhibitors of SARS-CoV-2 infection.


Assuntos
COVID-19 , SARS-CoV-2 , Antivirais , Humanos , Simulação de Dinâmica Molecular , Peptídeos/metabolismo , Ligação Proteica , Glicoproteína da Espícula de Coronavírus/metabolismo
10.
Toxins (Basel) ; 13(5)2021 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-34065799

RESUMO

Colibactin is a secondary metabolite encoded by the pks gene island identified in several Enterobacteriaceae, including some pathogenic Escherichia coli (E. coli) commonly enriched in mucosal tissue collected from patients with inflammatory bowel disease and colorectal cancer. E. coli harboring this biosynthetic gene cluster cause DNA damage and tumorigenesis in cell lines and pre-clinical models, yet fundamental knowledge regarding colibactin function is lacking. To accurately assess the role of pks+ E. coli in cancer etiology, the biological mechanisms governing production and delivery of colibactin by these bacteria must be elucidated. In this review, we will focus on recent advances in our understanding of colibactin's structural mode-of-action and mutagenic potential with consideration for how this activity may be regulated by physiologic conditions within the intestine.


Assuntos
Enterobacteriaceae/metabolismo , Mutagênicos/metabolismo , Peptídeos/metabolismo , Policetídeos/metabolismo , Animais , Dano ao DNA , Enterobacteriaceae/genética , Humanos , Família Multigênica , Mutagênicos/toxicidade , Peptídeos/toxicidade , Policetídeos/toxicidade , Metabolismo Secundário
11.
Int J Mol Sci ; 22(10)2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-34063397

RESUMO

The Cellular Communication Network (CCN) family of matricellular proteins comprises six proteins that share conserved structural features and play numerous biological roles. These proteins can interact with several receptors or soluble proteins, regulating cell signaling pathways in various tissues under physiological and pathological conditions. In the skeletal muscle of mammals, most of the six CCN family members are expressed during embryonic development or in adulthood. Their roles during the adult stage are related to the regulation of muscle mass and regeneration, maintaining vascularization, and the modulation of skeletal muscle fibrosis. This work reviews the CCNs proteins' role in skeletal muscle physiology and disease, focusing on skeletal muscle fibrosis and its regulation by Connective Tissue Growth factor (CCN2/CTGF). Furthermore, we review evidence on the modulation of fibrosis and CCN2/CTGF by the renin-angiotensin system and the kallikrein-kinin system of vasoactive peptides.


Assuntos
Fator de Crescimento do Tecido Conjuntivo/metabolismo , Músculo Esquelético/fisiologia , Peptídeos/metabolismo , Animais , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Cininas/metabolismo , Família Multigênica , Proteínas Musculares/metabolismo , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/patologia , Atrofia Muscular/metabolismo , Atrofia Muscular/patologia , Doenças Musculares/metabolismo , Doenças Musculares/patologia , Regeneração , Sistema Renina-Angiotensina
12.
Viruses ; 13(5)2021 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-34069206

RESUMO

Multiple outbreaks of epidemic and pandemic viral diseases have occurred in the last 20 years, including those caused by Ebola virus, Zika virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The emergence or re-emergence of such diseases has revealed the deficiency in our pipeline for the discovery and development of antiviral drugs. One promising solution is the extensive library of antimicrobial peptides (AMPs) produced by all eukaryotic organisms. AMPs are widely known for their activity against bacteria, but many possess additional antifungal, antiparasitic, insecticidal, anticancer, or antiviral activities. AMPs could therefore be suitable as leads for the development of new peptide-based antiviral drugs. Sixty therapeutic peptides had been approved by the end of 2018, with at least another 150 in preclinical or clinical development. Peptides undergoing clinical trials include analogs, mimetics, and natural AMPs. The advantages of AMPs include novel mechanisms of action that hinder the evolution of resistance, low molecular weight, low toxicity toward human cells but high specificity and efficacy, the latter enhanced by the optimization of AMP sequences. In this opinion article, we summarize the evidence supporting the efficacy of antiviral AMPs and discuss their potential to treat emerging viral diseases including COVID-19.


Assuntos
COVID-19/tratamento farmacológico , Proteínas Citotóxicas Formadoras de Poros/farmacologia , SARS-CoV-2/efeitos dos fármacos , Antivirais/farmacologia , Humanos , Pandemias , Peptídeos/metabolismo , Peptídeos/farmacologia , Proteínas Citotóxicas Formadoras de Poros/metabolismo , SARS-CoV-2/metabolismo , Viroses/tratamento farmacológico
13.
Inorg Chem ; 60(13): 9309-9319, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34109781

RESUMO

Catalases (CAT) are antioxidant metalloenzymes necessary for life in oxygen-metabolizing cells to regulate H2O2 concentration by accelerating its dismutation. Many physiopathological situations are associated with oxidative stress resulting from H2O2 overproduction, during which antioxidant defenses are overwhelmed. We have used a combinatorial approach associated with an activity-based screening to discover a first peptidyl di-copper complex mimicking CAT. The complex was studied in detail and characterized for its CAT activity both in solutions and in cells using different analytical methods. The complex exhibited CAT activity in solutions and, more interestingly, on HyPer HeLa cells that possess a genetically encoded ratiometric fluorescent sensors of H2O2. These results highlight the efficiency of a combinatorial approach for the discovery of peptidyl complexes that exhibit catalytic activity.


Assuntos
Antioxidantes/metabolismo , Catalase/metabolismo , Cobre/metabolismo , Metaloproteínas/metabolismo , Peptídeos/metabolismo , Antioxidantes/química , Catalase/química , Cobre/química , Células HeLa , Humanos , Peróxido de Hidrogênio/metabolismo , Metaloproteínas/química , Peptídeos/química , Células Tumorais Cultivadas
14.
Viruses ; 13(5)2021 05 14.
Artigo em Inglês | MEDLINE | ID: covidwho-1234826

RESUMO

Multiple outbreaks of epidemic and pandemic viral diseases have occurred in the last 20 years, including those caused by Ebola virus, Zika virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The emergence or re-emergence of such diseases has revealed the deficiency in our pipeline for the discovery and development of antiviral drugs. One promising solution is the extensive library of antimicrobial peptides (AMPs) produced by all eukaryotic organisms. AMPs are widely known for their activity against bacteria, but many possess additional antifungal, antiparasitic, insecticidal, anticancer, or antiviral activities. AMPs could therefore be suitable as leads for the development of new peptide-based antiviral drugs. Sixty therapeutic peptides had been approved by the end of 2018, with at least another 150 in preclinical or clinical development. Peptides undergoing clinical trials include analogs, mimetics, and natural AMPs. The advantages of AMPs include novel mechanisms of action that hinder the evolution of resistance, low molecular weight, low toxicity toward human cells but high specificity and efficacy, the latter enhanced by the optimization of AMP sequences. In this opinion article, we summarize the evidence supporting the efficacy of antiviral AMPs and discuss their potential to treat emerging viral diseases including COVID-19.


Assuntos
COVID-19/tratamento farmacológico , Proteínas Citotóxicas Formadoras de Poros/farmacologia , SARS-CoV-2/efeitos dos fármacos , Antivirais/farmacologia , Humanos , Pandemias , Peptídeos/metabolismo , Peptídeos/farmacologia , Proteínas Citotóxicas Formadoras de Poros/metabolismo , SARS-CoV-2/metabolismo , Viroses/tratamento farmacológico
15.
J Phys Chem B ; 125(24): 6572-6586, 2021 06 24.
Artigo em Inglês | MEDLINE | ID: covidwho-1265912

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has evolved into a pandemic of unprecedented scale. This coronavirus enters cells by the interaction of the receptor binding domain (RBD) with the human angiotensin-converting enzyme 2 receptor (hACE2). In this study, we employed a rational structure-based design to propose 22-mer stapled peptides using the structure of the hACE2 α1 helix as a template. These peptides were designed to retain the α-helical character of the natural structure, to enhance binding affinity, and to display a better solubility profile compared to other designed peptides available in the literature. We employed different docking strategies (PATCHDOCK and ZDOCK) followed by a double-step refinement process (FIBERDOCK) to rank our peptides, followed by stability analysis/evaluation of the interaction profile of the best docking predictions using a 500 ns molecular dynamics (MD) simulation, and a further binding affinity analysis by molecular mechanics with generalized Born and surface area (MM/GBSA) method. Our most promising stapled peptides presented a stable profile and could retain important interactions with the RBD in the presence of the E484K RBD mutation. We predict that these peptides can bind to the viral RBD with similar potency to the control NYBSP-4 (a 30-mer experimentally proven peptide inhibitor). Furthermore, our study provides valuable information for the rational design of double-stapled peptide as inhibitors of SARS-CoV-2 infection.


Assuntos
COVID-19 , SARS-CoV-2 , Antivirais , Humanos , Simulação de Dinâmica Molecular , Peptídeos/metabolismo , Ligação Proteica , Glicoproteína da Espícula de Coronavírus/metabolismo
16.
Food Chem ; 362: 130249, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34111693

RESUMO

This study aimed to isolate and identify peptides with intense umami taste from tilapia lower jaw. The aqueous extract was separated using ultrafiltration and Sephadex G-15 gel filtration chromatography. The peptide fraction with an intense umami taste was selected by sensory evaluation. The five novel peptides with strong umami taste were VADLMR, STELFK, FVGLQER, DALKKK, and VVLNPVARVE. Electronic tongue analysis and sensory evaluation showed that five peptides had obvious umami taste characteristics, and the recognition thresholds of umami peptides were in the range 0.125-0.250 mg/mL. Molecular docking was used to study the interaction of the peptides and umami taste receptor T1R1/T1R3. The five peptides could perfectly be inserted into the binding pocket of the Venus flytrap domain in the T1R3 subunit. Hydrogen bonding and hydrophobic interaction were the important interaction forces. The five peptides may bind with Asp219, Glu217, and Glu148 in T1R1/T1R3 receptor and produce the umami taste.


Assuntos
Arcada Osseodentária/química , Peptídeos/química , Peptídeos/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animais , Cromatografia em Gel , Nariz Eletrônico , Simulação de Acoplamento Molecular , Ligação Proteica , Paladar , Tilápia
17.
Food Chem ; 362: 130262, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34118509

RESUMO

Infant biscuits (IBs) are commonly used during the complementary feeding of infants from the 6th month of life. They contain wheat flour and dairy ingredients, which can release the opioid-acting peptides ß-casomorphins (BCMs) and gluten exorphins (GEs) after gastrointestinal digestion. In the present study, five model IBs were prepared with or without gluten and different powdered milk derivatives in the formulations. IBs were digested simulating an in vitro static gastrointestinal digestion for infants aged 6-12 months. BCMs and GEs were identified and quantified by UPLC/HR-MS. The amounts of BCM7 and the GE A5 were related to the ß-CN and gluten content of the formulations. To date, levels of BCMs and GEs in digests of IBs have not been reported in literature. This work represents an in vitro investigation regarding the release of opioid-acting peptides in IBs. It could add additional knowledge on complementary foods for infant health.


Assuntos
Digestão , Endorfinas/metabolismo , Alimentos Infantis/análise , Peptídeos/química , Animais , Laticínios , Farinha , Glutens/química , Humanos , Lactente , Alimentos Infantis/normas , Leite/química , Peptídeos/análise , Peptídeos/metabolismo
18.
Food Chem ; 362: 130098, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34090041

RESUMO

The specificity of pepsin, the major protease of gastric digestion, has been previously investigated, but only regarding the primary sequence of the protein substrates. The present study aimed to consider in addition physicochemical and structural characteristics, at the molecular and sub-molecular scales. For six different proteins submitted to in vitro gastric digestion, the peptide bonds cleaved were determined from the peptides released and identified by LC-MS/MS. An original statistical approach, based on propensity scores calculated for each amino acid residue on both sides of the peptide bonds, concluded that preferential cleavage occurred after Leu and Phe, and before Ile. Moreover, reliable statistical models developed for predicting peptide bond cleavage, highlighted the predominant role of the amino acid residues at the N-terminal side of the peptide bonds, up to the seventh position (P7 and P7'). The significant influence of hydrophobicity, charge and structural constraints around the peptide bonds was also evidenced.


Assuntos
Pepsina A/metabolismo , Proteínas/metabolismo , Sequência de Aminoácidos , Aminoácidos , Cromatografia Líquida , Endopeptidases/metabolismo , Modelos Estatísticos , Peptídeos/metabolismo , Proteínas/química , Proteólise , Especificidade por Substrato , Espectrometria de Massas em Tandem
19.
Nat Commun ; 12(1): 3810, 2021 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-34155216

RESUMO

To a large extent functional diversity in cells is achieved by the expansion of molecular complexity beyond that of the coding genome. Various processes create multiple distinct but related proteins per coding gene - so-called proteoforms - that expand the functional capacity of a cell. Evaluating proteoforms from classical bottom-up proteomics datasets, where peptides instead of intact proteoforms are measured, has remained difficult. Here we present COPF, a tool for COrrelation-based functional ProteoForm assessment in bottom-up proteomics data. It leverages the concept of peptide correlation analysis to systematically assign peptides to co-varying proteoform groups. We show applications of COPF to protein complex co-fractionation data as well as to more typical protein abundance vs. sample data matrices, demonstrating the systematic detection of assembly- and tissue-specific proteoform groups, respectively, in either dataset. We envision that the presented approach lays the foundation for a systematic assessment of proteoforms and their functional implications directly from bottom-up proteomic datasets.


Assuntos
Isoformas de Proteínas/análise , Proteômica/métodos , Algoritmos , Animais , Benchmarking , Humanos , Camundongos , Peptídeos/análise , Peptídeos/metabolismo , Isoformas de Proteínas/metabolismo , Proteômica/normas , Espectrometria de Massas em Tandem , Fluxo de Trabalho
20.
Int J Mol Sci ; 22(9)2021 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-34067001

RESUMO

Investigations into the mechanisms regulating obesity are frantic and novel translational approaches are needed. The raccoon dog (Nyctereutes procyonoides) is a canid species representing a promising model to study metabolic regulation in a species undergoing cycles of seasonal obesity and fasting. To understand the molecular mechanisms of metabolic regulation in seasonal adaptation, we analyzed key central nervous system and peripheral signals regulating food intake and metabolism from raccoon dogs after autumnal fattening and winter fasting. Expressions of neuropeptide Y (NPY), orexin-2 receptor (OX2R), pro-opiomelanocortin (POMC) and leptin receptor (ObRb) were analyzed as examples of orexigenic and anorexigenic signals using qRT-PCR from raccoon dog hypothalamus samples. Plasma metabolic profiles were measured with 1H NMR-spectroscopy and LC-MS. Circulating hormones and cytokines were determined with canine specific antibody assays. Surprisingly, NPY and POMC were not affected by the winter fasting nor autumn fattening and the metabolic profiles showed a remarkable equilibrium, indicating conserved homeostasis. However, OX2R and ObRb expression changes suggested seasonal regulation. Circulating cytokine levels were not increased, demonstrating that the autumn fattening did not induce subacute inflammation. Thus, the raccoon dog developed seasonal regulatory mechanisms to accommodate the autumnal fattening and prolonged fasting making the species unique in coping with the extreme environmental challenges.


Assuntos
Adiposidade , Jejum/metabolismo , Metaboloma , Cães Guaxinins/metabolismo , Estações do Ano , Tecido Adiposo/irrigação sanguínea , Tecido Adiposo/patologia , Animais , Biomarcadores/metabolismo , Peso Corporal , Análise Discriminante , Feminino , Hormônios/sangue , Hipotálamo/metabolismo , Inflamação/patologia , Análise dos Mínimos Quadrados , Limite de Detecção , Análise Multivariada , Peptídeos/genética , Peptídeos/metabolismo , Espectroscopia de Prótons por Ressonância Magnética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Cães Guaxinins/sangue , Receptores de Peptídeos/metabolismo
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