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1.
Food Chem ; 334: 127603, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32712492

RESUMO

Present work comprises the use of different solid-state Nuclear Magnetic Resonance strategies for characterizing structural and motional aspects of the peptide matrix that compose a set of four lyophilized Mexican cheese aqueous soluble extracts, each with a controlled ripening. Heteronuclear dipolar coupling modulation schemes allowed to characterize local mobility and structural homogeneity of cheeses' peptide segments in the solid-state as a function of ripening. Results suggest that ripened samples with certain local flexibility but important structural homogeneity present efficient microbial inhibition against tested bacterial strains, whilst high local rigidity of peptides within ripened cheese soluble fractions could partially explain the observed lack of antimicrobial activity. The present study attempts to propose novel observables for lyophilized cheese water soluble extracts that could be partially associated to their ripening-dependent antimicrobial activities, whereas said observables shall contribute to the better targeting, design and optimization of solid-state natural food bio-preservatives.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Queijo , Espectroscopia de Ressonância Magnética/métodos , Anti-Infecciosos/análise , Isótopos de Carbono , Queijo/análise , Liofilização , Testes de Sensibilidade Microbiana , Peptídeos/análise , Peptídeos/química , Peptídeos/farmacologia , Solubilidade , Água
2.
Food Chem ; 334: 127554, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32711267

RESUMO

In this study, the targeted regulatory mechanism of pulsed electric field (PEF) was explored for antioxidant activity improvement in four peptides, RGAVIH, RGAVLH, VNAVIH, and VNAVLH, of the pine nut (Pinus koraiensis Sieb. et Zucc). The VNAVLH peptide exhibited the best antioxidant activity and the ß-sheet content decreased to a minimum value at 40 kV/cm. Moreover, the chemical shifts of hydrogen atoms of 2-H Asn and 6-H His shifted to a higher magnetic field. The connectivity between NαH (3.62 ppm) and CαH (8.10 ppm) of 6-His residue disappeared in PEF-treated peptide. Molecule dynamics (MD) simulation verified that the distances of Nα(H78)-Cα(H80) and H82-O94 increased, whereas -OH and -Cß(H83) got closer in histidine residue after applying the electric field force. Therefore, the antioxidant activity enhancement of VNAVLH might due to the targeted regulation of PEF treatment on NαH-CαH and imidazole group in histidine.


Assuntos
Histidina/química , Nozes/metabolismo , Peptídeos/química , Pinus/metabolismo , Sequência de Aminoácidos , Antioxidantes/química , Espectroscopia de Ressonância Magnética , Simulação de Dinâmica Molecular , Conformação Proteica em Folha beta
3.
Food Chem ; 335: 127610, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32738532

RESUMO

Although collagen peptides have been proved to possess wide applications in functional foods, cosmetics, medical materials and pharmaceuticals, the production of collagen peptides are deeply affected by proteases and substrate. In this study, the scalable-synthesis sulfonated polystyrene (SPS) nanospheres were utilized as accessible supports for efficient subtilisin immobilization. Detailed characterizations through SEM-EDS, TEM, TGA and FT-IR confirmed the undamaged formation of the SPS-subtilisin. Owing to the moderate hydrophobic effect and electrostatic interaction, the SPS-subtilisin could achieve 397.15 mg/g enzyme loading and 77.3% activity recovery. The tilapia skin collagen, as a resource-rich raw material, was hydrolyzed by the prepared immobilized subtilisin. The antioxidant activity of the attained peptides was verified. With the mass spectrometry and molecular docking analysis of product peptides sequences, representative peptides were synthesized and their anti-oxidation capacity and mechanism were affirmed, which further verified the undiminished catalytic ability of immobilized subtilisin.


Assuntos
Colágeno/química , Nanosferas/química , Peptídeo Hidrolases/química , Peptídeos/química , Poliestirenos/química , Catálise , Endopeptidases/química , Enzimas Imobilizadas/química , Interações Hidrofóbicas e Hidrofílicas , Simulação de Acoplamento Molecular , Espectroscopia de Infravermelho com Transformada de Fourier
4.
Vestn Otorinolaringol ; 85(5): 57-60, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33140935

RESUMO

Acute respiratory infections (ORI) consistently occupy one of the leading places among infectious and inflammatory diseases in children. Most often, antibacterial drugs are used to stop the inflammatory process in the pharynx. Cationic peptides have an extremely broad antimicrobial spectrum, rendering the effect not only in bacterial infections and mycoses, and protozoans. THE PURPOSE OF THE STUDY: To demonstrate that the test drug is effective and safe for the treatment of acute viral pharyngitis in childhood. MATERIALS AND METHODS: In the period from September 2019 to January 2020, 120 patients aged 6 to 18 years were treated with the drug «Doritricin¼ for viral pharyngitis. RESULTS: According to the research results it can be concluded that «Diretrizes¼ provides fast and high effect in pediatric practice.


Assuntos
Faringite , Infecções Respiratórias , Infecções Estreptocócicas , Adolescente , Antibacterianos/uso terapêutico , Criança , Humanos , Peptídeos , Faringite/tratamento farmacológico , Faringe , Infecções Respiratórias/tratamento farmacológico , Infecções Estreptocócicas/tratamento farmacológico , Streptococcus pyogenes
5.
Science ; 370(6518): 767-768, 2020 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-33184194
6.
Nat Commun ; 11(1): 5357, 2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-33097721

RESUMO

Low-density lipoprotein receptor-related protein 6 (LRP6) is a coreceptor of the ß-catenin-dependent Wnt signaling pathway. The LRP6 ectodomain binds Wnt proteins, as well as Wnt inhibitors such as sclerostin (SOST), which negatively regulates Wnt signaling in osteocytes. Although LRP6 ectodomain 1 (E1) is known to interact with SOST, several unresolved questions remain, such as the reason why SOST binds to LRP6 E1E2 with higher affinity than to the E1 domain alone. Here, we present the crystal structure of the LRP6 E1E2-SOST complex with two interaction sites in tandem. The unexpected additional binding site was identified between the C-terminus of SOST and the LRP6 E2 domain. This interaction was confirmed by in vitro binding and cell-based signaling assays. Its functional significance was further demonstrated in vivo using Xenopus laevis embryos. Our results provide insights into the inhibitory mechanism of SOST on Wnt signaling.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/antagonistas & inibidores , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteínas Wnt/metabolismo , Via de Sinalização Wnt/efeitos dos fármacos , Proteínas Adaptadoras de Transdução de Sinal/química , Animais , Sítios de Ligação , Cristalografia por Raios X , Feminino , Células HEK293 , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/química , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/química , Modelos Moleculares , Peptídeos/metabolismo , Ligação Proteica , Conformação Proteica , Transcriptoma , Xenopus laevis/embriologia , Xenopus laevis/metabolismo , beta Catenina/metabolismo
7.
Cell Death Dis ; 11(10): 921, 2020 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-33110074

RESUMO

The immunological mechanisms underlying the clinical presentation of SARS-CoV-2 infection and those influencing the disease outcome remain to be defined. Myeloid-derived suppressor cells (MDSC) have been described to be highly increased during COVID-19, however, their role remains elusive. We performed an in depth analysis of MDSC in 128 SARS-CoV-2 infected patients. Polymorphonuclear (PMN)-MDSC expanded during COVID-19, in particular in patients who required intensive care treatments, and correlated with IL-1ß, IL-6, IL-8, and TNF-α plasma levels. PMN-MDSC inhibited T-cells IFN-γ production upon SARS-CoV-2 peptides stimulation, through TGF-ß- and iNOS-mediated mechanisms, possibly contrasting virus elimination. Accordingly, a multivariate regression analysis found a strong association between PMN-MDSC percentage and fatal outcome of the disease. The PMN-MDSC frequency was higher in non-survivors than survivors at the admission time, followed by a decreasing trend. Interestingly, this trend was associated with IL-6 increase in non-survivors but not in survivors. In conclusion, this study indicates PMN-MDSC as a novel factor in the pathogenesis of SARS-CoV2 infection, and open up to new therapeutic options.


Assuntos
Betacoronavirus/imunologia , Infecções por Coronavirus/patologia , Células Supressoras Mieloides/imunologia , Pneumonia Viral/patologia , Linfócitos T/imunologia , Idoso , Área Sob a Curva , Betacoronavirus/isolamento & purificação , Betacoronavirus/metabolismo , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/mortalidade , Infecções por Coronavirus/virologia , Feminino , Humanos , Interferon gama/metabolismo , Interleucina-1beta/sangue , Interleucina-6/sangue , Masculino , Pessoa de Meia-Idade , Células Supressoras Mieloides/citologia , Neutrófilos/citologia , Neutrófilos/imunologia , Neutrófilos/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Pandemias , Peptídeos/imunologia , Peptídeos/metabolismo , Pneumonia Viral/imunologia , Pneumonia Viral/mortalidade , Pneumonia Viral/virologia , Modelos de Riscos Proporcionais , Curva ROC , Taxa de Sobrevida , Linfócitos T/citologia , Linfócitos T/metabolismo , Fator de Crescimento Transformador beta/sangue , Fator de Crescimento Transformador beta/metabolismo
8.
Vestn Oftalmol ; 136(5): 58-66, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33056965

RESUMO

PURPOSE: To evaluate the influence of prolonged neuroprotective therapy on disease progression in patients with primary open-angle glaucoma (POAG) with compensated intraocular pressure (IOP). MATERIAL AND METHODS: The study included 147 patients with stages I-II POAG (249 eyes) who were randomized into the main (69 patients, 119 eyes) and control groups (78 patients, 130 eyes). Patients of the main group underwent retinalamin treatment course every 6 months. Patients were examined before enrolling and then every 3 months during the 24-months follow-up including optical coherence tomography (OCT; RNFL - retinal nerve fiber layer, NRR - neuroretinal rim, GCL - ganglion cell layer) and static perimetry (MD - mean deviation, PSD - pattern standard deviation). RESULTS: Visual acuity and refraction did not change in either group (p>0.05). IOP increased in the control group (p=0.033). There was no difference between the groups by the 24th month (p=0.87). No MD changes were noted in the main (p=0.45) and control groups (p=0.27). PSD changed in the main (4.84±3.21 and 6.01±2.584 dB in the beginning and the end, respectively, p=0.0004) and the control groups (3.46±2.23 and 5.86±2.26 dB, respectively; p<0.0001). The groups differed in MD and PSD initially (p=0.15; p=0.02) and became equal by the end (p=0.59; p=0.53). RNFL did not change significantly in the main group (p=0.078) and decreased from 83.5±22.47 to 76.7±20.7 µm in the control group (p=0.001); no differences between the groups were noted in the beginning (p=0.276) or in the end of the study (p=0.524). NRR increased in the main group from 222±88.94 to 231±99.3 (p=0.012), and decreased in the control group from 248±87.09 to 234±96.2 (p=0.0006); no differences were found between groups in the beginning or in the end of the study (p=0.109; p=0.909). GCL thickness did not change either in the main, or in the control group (p=0.211; p=0.16), with no difference between the group noted in the beginning or the end of the study (p=0.44; p=0.51). CONCLUSION: Regular treatment with retinalamin arrests the development of glaucomatous optic neuropathy. Longer-term research is required to study its influence on the visual function and the quality of life.


Assuntos
Glaucoma , Peptídeos , Qualidade de Vida , Progressão da Doença , Humanos , Fibras Nervosas , Peptídeos/uso terapêutico , Células Ganglionares da Retina , Tomografia de Coerência Óptica , Acuidade Visual
9.
Nat Commun ; 11(1): 4955, 2020 10 02.
Artigo em Inglês | MEDLINE | ID: mdl-33009385

RESUMO

The light-harvesting-reaction center complex (LH1-RC) from the purple phototrophic bacterium Thiorhodovibrio strain 970 exhibits an LH1 absorption maximum at 960 nm, the most red-shifted absorption for any bacteriochlorophyll (BChl) a-containing species. Here we present a cryo-EM structure of the strain 970 LH1-RC complex at 2.82 Å resolution. The LH1 forms a closed ring structure composed of sixteen pairs of the αß-polypeptides. Sixteen Ca ions are present in the LH1 C-terminal domain and are coordinated by residues from the αß-polypeptides that are hydrogen-bonded to BChl a. The Ca2+-facilitated hydrogen-bonding network forms the structural basis of the unusual LH1 redshift. The structure also revealed the arrangement of multiple forms of α- and ß-polypeptides in an individual LH1 ring. Such organization indicates a mechanism of interplay between the expression and assembly of the LH1 complex that is regulated through interactions with the RC subunits inside.


Assuntos
Cálcio/metabolismo , Microscopia Crioeletrônica , Complexos de Proteínas Captadores de Luz/ultraestrutura , Peptídeos/metabolismo , Fotossíntese , Sequência de Aminoácidos , Bacterioclorofila A/metabolismo , Sítios de Ligação , Chromatiaceae/metabolismo , Detergentes/química , Dimerização , Complexos de Proteínas Captadores de Luz/química , Complexos de Proteínas Captadores de Luz/metabolismo , Lipídeos/química , Peptídeos/química , Quinonas/química
10.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 55(10): 757-764, 2020 Oct 09.
Artigo em Chinês | MEDLINE | ID: mdl-33045788

RESUMO

Objective: To investigate the effect of RATEA16 scaffold on the proliferation of human umbilical vein endothelial cells (HUVEC) and the effect of new self-assembling peptide hydrogel (RATEA16) scaffold with vascular endothelial growth factor (VEGF) on promoting angiogenesis. Methods: RATEA16 hydrogel was prepared, then the injectability, microstructure, degradation, biocompatibility of RATEA16 hydrogel were determined. HUVEC were cultured with RATEA16 scaffold to detect cell morphology and proliferation. HUVEC were cultured on RATEA16 scaffold with VEGF for 24 h. The expression of VEGF-A, von Willebrand factor (vWF), matrix metalloproteinase-9 (MMP-9) and platelet endothelial cell adhesion molecule-1 (PECAM-1) were detected by using real-time PCR to evaluate the effects of the scaffold with VEGF system on HUVEC differentiation. Results: The sol-gel transition was completed under neutral condition (pH=7.4) adjusted by Tris-HCl solution. The hydrogel could be easily injected from a syringe. It presented a porous and interconnected internal structure and the porosity of the scaffold was (67.3±9.4)%. After 4 week degradation in vitro, the residual weight was still (82.354±0.006)%, which exhibited slow degradation. HUVEC grew well after being cultured in leach liquor of RATEA16 hydrogel for 24 h, and there was no significant difference in HUVEC cell viability compared with that of the control group (P>0.05). HUVEC encapsulated in RATEA16 hydrogel appeared round in shape and exhibited effectively continuous proliferation. When HUVEC were cultured on RATEA16 hydrogel with VEGF for 24 h, the formation of vascular-like structures was observed. The expression of VEGF-A and MMP-9 was 1.5-2.0 times that of control group, and vWF was 10 times and PECAM-1 was 55 times compared with that of the control group (P<0.05). Conclusions: The RATEA16 hydrogel used in this study could be prepared by simply adjusting pH to neutral. This hydrogel exhibited good biodegradability, slow degradation and injectability. HUVEC might attach and spread in RATEA16 scaffold. The RATEA16 scaffold with VEGF could promote angiogenic differentiation of HUVEC. The novel scaffold is expected to achieve the critical vascularization process in bone tissue regeneration.


Assuntos
Hidrogéis , Fator A de Crescimento do Endotélio Vascular , Células Endoteliais da Veia Umbilical Humana , Humanos , Peptídeos/farmacologia , Veias Umbilicais
11.
Toxicon ; 188: 95-107, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33065200

RESUMO

Crotamine and crotamine-like peptides are non-enzymatic polypeptides, belonging to the family of myotoxins, which are found in high concentration in the venom of the Crotalus genus. Helleramine was isolated and purified from the venom of the Southern Pacific rattlesnake, Crotalus oreganus helleri. This peptide had a similar, but unique, identity to crotamine and crotamine-like proteins isolated from other rattlesnakes species. The variability of crotamine-like protein amino acid sequences may allow different toxic effects on biological targets or optimize the action against the same target of different prey. Helleramine was capable of increasing intracellular Ca2+ in Chinese Hamster Ovary (CHO) cell line. It inhibited cell migration as well as cell viability (IC50 = 11.44 µM) of C2C12, immortalized skeletal myoblasts, in a concentration dependent manner, and promoted early apoptosis and cell death under our experimental conditions. Skeletal muscle harvested from mice 24 h after helleramine injection showed contracted myofibrils and profound vacuolization that enlarged the subsarcolemmal space, along with loss of plasmatic and basal membrane integrity. The effects of helleramine provide further insights and evidence of myotoxic activities of crotamine-like peptides and their possible role in crotalid envenomings.


Assuntos
Venenos de Crotalídeos/farmacologia , Crotalus , Placa Motora/efeitos dos fármacos , Músculo Estriado/efeitos dos fármacos , Sequência de Aminoácidos , Animais , Células CHO , Linhagem Celular , Cricetulus , Camundongos , Placa Motora/ultraestrutura , Músculo Estriado/ultraestrutura , Peptídeos
12.
Toxicon ; 188: 55-64, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33068557

RESUMO

Hepatitis C virus (HCV) is a global viral widespread without an available vaccine to prevent infection. HCV infection can cause serious liver diseases such as hepatocellular carcinoma (HCC). Current treatment of HCV infection depends on the FDA approved direct-acting antivirals (DAAs) which have side effects and expensive. Thus, development of a novel, more efficient, along with affordable pricing anti-HCV agents is still required. The purpose of the present study is to evaluate the antiviral effects of bee venom (BV) from the honeybee Apis mellifera on the HCV replication life cycle. The crude venom and its components were examined for their anti-HCV activities using Huh7it-1 cultured cells and the JFH1 strain of HCV genotype 2a. Results revealed that BV inhibited HCV infection with 50% inhibitory concentration (IC50) of 0.05 ng/ml, while the 50% cytotoxic concentration (CC50) being 20,000 ng/ml. The venom directly blocked HCV/cell entry by acting on virus particles in a dose dependent manner, whereas no interference on the host cells. Furthermore, venom showed no inhibitory effect on HCV replication and release. Interestingly, none of the main BV components including the mast cell degranulating peptide (MCD), mpamin, or the small peptides melittin (MLT) showed anti-HCV activity up to 5 µg/ml. In conclusion, these results suggest that BV has a direct virucidal activity against HCV and may exert its antiviral effect through a non-common peptide(s) or toxin complex within the crude venom. Therefore, the crude BV can be considered as a promising candidate for characterization and development of new and natural anti-HCV therapeutic agents.


Assuntos
Antivirais/farmacologia , Venenos de Abelha/farmacologia , Abelhas , Hepatite C Crônica , Animais , Carcinoma Hepatocelular , Linhagem Celular , Hepacivirus , Hepatite C , Neoplasias Hepáticas , Meliteno , Peptídeos
13.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 2217-2220, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018448

RESUMO

Type 1 diabetic patients characteristically exhibit a loss of insulin production, leading to chronic hyperglycemia and related complications. Herein we describe the design, synthesis and screening of novel oligopeptides for their potential to enhance the secretion of insulin from human pancreatic islets. The investigation of these compounds, based off the patented INGAP-PP sequence, aims to identify the peptide features key to maximizing insulin secretion.Clinical Relevance - This report describes the relative efficacy of selected novel compounds for potential Type 1 Diabetes Therapy. Tested on live human pancreatic islets, the compounds are evaluated for their enhancing/inhibitory effect on the secretion of insulin. These studies pave the way for future targeted drug therapies.


Assuntos
Diabetes Mellitus Tipo 1 , Ilhotas Pancreáticas , Diabetes Mellitus Tipo 1/tratamento farmacológico , Humanos , Insulina/metabolismo , Secreção de Insulina , Ilhotas Pancreáticas/metabolismo , Peptídeos/metabolismo
14.
Nucleic Acids Res ; 48(19): 10662-10679, 2020 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-33010175

RESUMO

Potent knockdown of pathogenic RNA in vivo is an urgent health need unmet by both small-molecule and biologic drugs. 'Smart' supramolecular assembly of catalysts offers precise recognition and potent destruction of targeted RNA, hitherto not found in nature. Peptidyl-oligonucleotide ribonucleases are here chemically engineered to create and attack bulge-loop regions upon hybridization to target RNA. Catalytic peptide was incorporated either via a centrally modified nucleotide (Type 1) or through an abasic sugar residue (Type 2) within the RNA-recognition motif to reveal striking differences in biological performance and strict structural demands of ribonuclease activity. None of the Type 1 conjugates were catalytically active, whereas all Type 2 conjugates cleaved RNA target in a sequence-specific manner, with up to 90% cleavage from 5-nt bulge-loops (BC5-α and BC5L-ß anomers) through multiple cuts, including in folds nearby. Molecular dynamics simulations provided structural explanation of accessibility of the RNA cleavage sites to the peptide with adoption of an 'in-line' attack conformation for catalysis. Hybridization assays and enzymatic probing with RNases illuminated how RNA binding specificity and dissociation after cleavage can be balanced to permit turnover of the catalytic reaction. This is an essential requirement for inactivation of multiple copies of disease-associated RNA and therapeutic efficacy.


Assuntos
Oligonucleotídeos/química , Peptídeos/química , RNA/química , Ribonucleases/química , Domínio Catalítico , Técnicas de Silenciamento de Genes/métodos , Simulação de Dinâmica Molecular , Peptídeos/metabolismo , Ribonucleases/metabolismo
15.
Artigo em Alemão | MEDLINE | ID: mdl-33095280

RESUMO

Currently, extract-based therapeutic allergens from natural allergen sources (e.g., house dust mites, tree and grass pollen) are used for allergen-specific immunotherapy (AIT), the only causative therapy that can exhibit positive disease-modifying effects by tolerance induction and prevention of disease progression. Due to variations in the natural composition of the starting materials and different manufacturing processes, there are variations in protein content, allergen composition, and allergenic activity of similar products, which poses specific challenges for their standardization. The identification of the nucleotide sequences of allergenic proteins led to the development of molecular AIT approaches. This allows for the application of exclusively relevant structures as chemically synthesized peptides, recombinant single allergens, or molecules with hypoallergenic properties that potentially allow for an up-dosing with higher allergen-doses without allergic side effects leading more quickly to effective cumulative doses. Further modifications of AIT preparations to improve allergenic and immunogenic properties may be achieved, e.g., by including the use of virus-like particles (VLPs). To date, the herein described therapeutic approaches have been tested in clinical trials only. This article provides an overview of published molecular approaches for allergy treatment used in clinical AIT studies. Their added value and challenges compared to established therapeutic allergens are discussed. The aim of these approaches is to develop highly effective and well-tolerated AIT preparations with improved patient acceptance and adherence.


Assuntos
Alérgenos , Hipersensibilidade , Dessensibilização Imunológica , Alemanha , Humanos , Hipersensibilidade/terapia , Imunoterapia , Peptídeos
16.
J Phys Chem B ; 124(44): 9785-9792, 2020 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-33095007

RESUMO

Over 50 peptides, which were known to inhibit SARS-CoV-1, were computationally screened against the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2. Based on the binding affinity and interaction, 15 peptides were selected, which showed higher affinity compared to the α-helix of the human ACE2 receptor. Molecular dynamics simulation demonstrated that two peptides, S2P25 and S2P26, were the most promising candidates, which could potentially block the entry of SARS-CoV-2. Tyr489 and Tyr505 residues present in the "finger-like" projections of the RBD were found to be critical for peptide interaction. Hydrogen bonding and hydrophobic interactions played important roles in prompting peptide-protein binding and interaction. Structure-activity relationship indicated that peptides containing aromatic (Tyr and Phe), nonpolar (Pro, Gly, Leu, and Ala), and polar (Asn, Gln, and Cys) residues were the most significant contributors. These findings can facilitate the rational design of selective peptide inhibitors targeting the spike protein of SARS-CoV-2.


Assuntos
Antivirais/metabolismo , Betacoronavirus/química , Peptídeos/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Antivirais/química , Sítios de Ligação , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Estrutura Molecular , Peptídeos/química , Ligação Proteica , Domínios Proteicos , Glicoproteína da Espícula de Coronavírus/química , Relação Estrutura-Atividade
17.
Nat Commun ; 11(1): 5251, 2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-33067471

RESUMO

Data-independent acquisition (DIA) mass spectrometry, also known as Sequential Window Acquisition of all Theoretical Mass Spectra (SWATH), is a popular label-free proteomics strategy to comprehensively quantify peptides/proteins utilizing mass spectral libraries to decipher inherently multiplexed spectra collected linearly across a mass range. Although there are many spectral libraries produced worldwide, the quality control of these libraries is lacking. We present the DIALib-QC (DIA library quality control) software tool for the systematic evaluation of a library's characteristics, completeness and correctness across 62 parameters of compliance, and further provide the option to improve its quality. We demonstrate its utility in assessing and repairing spectral libraries for correctness, accuracy and sensitivity.


Assuntos
Espectrometria de Massas/métodos , Proteômica/métodos , Software , Humanos , Espectrometria de Massas/normas , Biblioteca de Peptídeos , Peptídeos/química , Peptídeos/genética , Proteínas/química , Proteínas/genética , Proteômica/normas
18.
PLoS One ; 15(9): e0238089, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32903266

RESUMO

A novel severe acute respiratory syndrome coronavirus (SARS-CoV-2) is the source of a current pandemic (COVID-19) with devastating consequences in public health and economic stability. Using a peptide array to map the antibody response of plasma from healing patients (12) and heathy patients (6), we identified three immunodominant linear epitopes, two of which correspond to key proteolytic sites on the spike protein (S1/S2 and S2') known to be critical for cellular entry. We show biochemical evidence that plasma positive for the epitope adjacent to the S1/S2 cleavage site inhibits furin-mediated proteolysis of spike.


Assuntos
Infecções por Coronavirus/patologia , Epitopos/química , Pneumonia Viral/patologia , Sequência de Aminoácidos , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Betacoronavirus/imunologia , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/virologia , Mapeamento de Epitopos , Epitopos/sangue , Epitopos/imunologia , Furina/metabolismo , Humanos , Pandemias , Ácidos Nucleicos Peptídicos/química , Peptídeos/química , Pneumonia Viral/virologia , Análise Serial de Proteínas , Estrutura Terciária de Proteína , Proteólise , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Alinhamento de Sequência , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo
19.
Nat Commun ; 11(1): 4554, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32917865

RESUMO

Non-ribosomal peptide synthetase (NRPS) enzymes form modular assembly-lines, wherein each module governs the incorporation of a specific monomer into a short peptide product. Modules are comprised of one or more key domains, including adenylation (A) domains, which recognise and activate the monomer substrate; condensation (C) domains, which catalyse amide bond formation; and thiolation (T) domains, which shuttle reaction intermediates between catalytic domains. This arrangement offers prospects for rational peptide modification via substitution of substrate-specifying domains. For over 20 years, it has been considered that C domains play key roles in proof-reading the substrate; a presumption that has greatly complicated rational NRPS redesign. Here we present evidence from both directed and natural evolution studies that any substrate-specifying role for C domains is likely to be the exception rather than the rule, and that novel non-ribosomal peptides can be generated by substitution of A domains alone. We identify permissive A domain recombination boundaries and show that these allow us to efficiently generate modified pyoverdine peptides at high yields. We further demonstrate the transferability of our approach in the PheATE-ProCAT model system originally used to infer C domain substrate specificity, generating modified dipeptide products at yields that are inconsistent with the prevailing dogma.


Assuntos
Monofosfato de Adenosina/metabolismo , Peptídeos/química , Peptídeos/metabolismo , Domínios Proteicos , Proteínas de Bactérias/metabolismo , Domínio Catalítico , Embaralhamento de DNA , Modelos Moleculares , Família Multigênica , Oligopeptídeos/química , Oligopeptídeos/metabolismo , Peptídeo Sintases/genética , Peptídeo Sintases/metabolismo , Conformação Proteica , Pseudomonas , Especificidade por Substrato
20.
Zhongguo Zhong Yao Za Zhi ; 45(16): 3883-3889, 2020 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-32893585

RESUMO

Shotgun based proteomics and peptidomics analysis were used to investigate the proteins and peptides in marine traditional Chinese medicine(TCM) Sepiae Endoconcha(cuttlebone). Peptides were extracted from cuttlebone by acidified methanol, and then strong cation exchange(SCX) resin was used to enrich those peptides. Also, proteins from cuttlebone were extracted and digested by trypsin. nano-LC Q Exactive Orbitrap mass spectrometry was used to analyze proteins and peptides from cuttlebone. As a result, a total of 16 proteins and 168 peptides were identified by protein database search, and 328 peptides were identified by De novo sequencing. The identified proteins were hemocyanin, enolase, myosin, actin, calmodulin, etc., and the identified peptides were derived from actin, histone, and tubulin. All these proteins and peptides were important components in cuttlebone, which would provide important theoretical and research basis for marine TCM cuttlebone investigations.


Assuntos
Peptídeos , Proteômica , Cátions , Bases de Dados de Proteínas , Espectrometria de Massas
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