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1.
Mol Pharm ; 21(5): 2097-2117, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38440998

RESUMO

Currently, one of the most significant and rapidly growing unmet medical challenges is the treatment of neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). This challenge encompasses the imperative development of efficacious therapeutic agents and overcoming the intricacies of the blood-brain barrier for successful drug delivery. Here we focus on the delivery aspect with particular emphasis on cell-penetrating peptides (CPPs), widely used in basic and translational research as they enhance drug delivery to challenging targets such as tissue and cellular compartments and thus increase therapeutic efficacy. The combination of CPPs with nanomaterials such as nanoparticles (NPs) improves the performance, accuracy, and stability of drug delivery and enables higher drug loads. Our review presents and discusses research that utilizes CPPs, either alone or in conjugation with NPs, to mitigate the pathogenic effects of neurodegenerative diseases with particular reference to AD and PD.


Assuntos
Barreira Hematoencefálica , Peptídeos Penetradores de Células , Sistemas de Liberação de Medicamentos , Nanopartículas , Doenças Neurodegenerativas , Doença de Parkinson , Peptídeos Penetradores de Células/química , Peptídeos Penetradores de Células/administração & dosagem , Humanos , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/efeitos dos fármacos , Sistemas de Liberação de Medicamentos/métodos , Nanopartículas/química , Doenças Neurodegenerativas/tratamento farmacológico , Animais , Doença de Parkinson/tratamento farmacológico , Doença de Alzheimer/tratamento farmacológico
2.
Biodegradation ; 35(4): 407-422, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38261084

RESUMO

The process of mechanically stirred membrane reactor containing the suspension of horseradish peroxidase (HRP) immobilized on synthesized nanocomposite (Tau-SiO2@Fe3O4-GO) was designed for continuous degradation of tetracycline. The immobilized HRP was characterized in terms of kinetic parameters and catalytic activities as these parameters were improved highly through immobilization. The stability indices including pH and temperature were investigated in parallel. The immobilized HRP was more tolerable to pH changes as compared to free HRP and the optimum temperature obtained at 40 °C. The reusability of HRP was promoted by immobilization as far as 70% of initial activity after ten cycles. The enzymatic degradation of optimum concentration of tetracycline was carried out in batch condition and 100% of tetracycline removed after 30 min. The results also showed that higher concentration of H2O2 exhibited more oxidation of tetracycline. The optimal ratio of HRP/H2O2 was also obtained at 0.005. The simultaneous process including separation and the biocatalytic degradation established in the membrane stirrer reactor concluded that no amount of tetracycline was observed in the permeate stream coming from the membrane after 30 min of operation.


Assuntos
Reatores Biológicos , Enzimas Imobilizadas , Peroxidase do Rábano Silvestre , Nanocompostos , Dióxido de Silício , Tetraciclina , Águas Residuárias , Enzimas Imobilizadas/metabolismo , Enzimas Imobilizadas/química , Nanocompostos/química , Tetraciclina/química , Peroxidase do Rábano Silvestre/química , Peroxidase do Rábano Silvestre/metabolismo , Dióxido de Silício/química , Águas Residuárias/química , Concentração de Íons de Hidrogênio , Poluentes Químicos da Água , Cinética , Peróxido de Hidrogênio/química , Membranas Artificiais , Temperatura , Antibacterianos/química
3.
J Biol Chem ; 298(3): 101662, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35104501

RESUMO

Alzheimer's disease is characterized by the presence of extraneuronal amyloid plaques composed of amyloid-beta (Aß) fibrillar aggregates in the brains of patients. In mouse models, it has previously been shown that atorvastatin (Ator), a cholesterol-lowering drug, has some reducing effect on the production of cerebral Aß. A meta-analysis on humans showed moderate effects in the short term but no improvement in the Alzheimer's Disease Assessment Scale-Cognitive Subscale behavioral test. Here, we explore a potential direct effect of Ator on Aß42 aggregation. Using NMR-based monomer consumption assays and CD spectroscopy, we observed a promoting effect of Ator in its original form (Ator-calcium) on Aß42 aggregation, as expected because of the presence of calcium ions. The effect was reversed when applying a CaCO3-based calcium ion scavenging method, which was validated by the aforementioned methods as well as thioflavin-T fluorescence assays and transmission electron microscopy. We found that the aggregation was inhibited significantly when the concentration of calcium-free Ator exceeded that of Aß by at least a factor of 2. The 1H-15N heteronuclear single quantum correlation and saturation-transfer difference NMR data suggest that calcium-free Ator exerts its effect through interaction with the 16KLVF19 binding site on the Aß peptide via its aromatic rings as well as hydroxyl and methyl groups. On the other hand, molecular dynamics simulations confirmed that the increasing concentration of Ator is necessary for the inhibition of the conformational transition of Aß from an α-helix-dominant to a ß-sheet-dominant structure.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Atorvastatina , Fragmentos de Peptídeos , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Atorvastatina/farmacologia , Cálcio/metabolismo , Humanos , Camundongos , Fragmentos de Peptídeos/metabolismo
4.
J Biol Chem ; 298(12): 102688, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36370848

RESUMO

Parkinson's disease is a neurodegenerative movement disorder associated with the intracellular aggregation of α-synuclein (α-syn). Cytotoxicity is mainly associated with the oligomeric species (αSOs) formed at early stages in α-syn aggregation. Consequently, there is an intense focus on the discovery of novel inhibitors such as peptides to inhibit oligomer formation and toxicity. Here, using peptide arrays, we identified nine peptides with high specificity and affinity for αSOs. Of these, peptides p194, p235, and p249 diverted α-syn aggregation from fibrils to amorphous aggregates with reduced ß-structures and increased random coil content. However, they did not reduce αSO cytotoxicity and permeabilization of large anionic unilamellar vesicles. In parallel, we identified a non-self-aggregating peptide (p216), derived from the cell-penetrating peptide penetratin, which showed 12-fold higher binding affinity to αSOs than to α-syn monomers (Kdapp 2.7 and 31.2 µM, respectively). p216 reduced αSOs-induced large anionic unilamellar vesicle membrane permeability at 10-1 to 10-3 mg/ml by almost 100%, was not toxic to SH-SY5Y cells, and reduced αSOs cytotoxicity by about 20%. We conclude that p216 is a promising starting point from which to develop peptides targeting toxic αSOs in Parkinson's disease.


Assuntos
Peptídeos Penetradores de Células , Doença de Parkinson , alfa-Sinucleína , Humanos , alfa-Sinucleína/metabolismo , Peptídeos Penetradores de Células/isolamento & purificação , Peptídeos Penetradores de Células/farmacologia , Doença de Parkinson/tratamento farmacológico , Doença de Parkinson/metabolismo , Linhagem Celular Tumoral
5.
Biotechnol Appl Biochem ; 69(6): 2496-2506, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34894353

RESUMO

Targeted drug therapy against cancer has been introduced as a smart strategy to combat the unwanted side effects due to systemic administration of chemotherapeutics. A human serum albumin (HSA)-based nanocarrier was fabricated with the aim to target reductive media and acidic pH of the tumor tissues. α-Lipoic acid (LA) was applied to increase the number of disulfide bonds in the nanocarrier to target higher glutathione concentrations present in tumor tissues and polyethylene glycol was used to target the acidic pH of tumors. UV illumination, ethanol desolvation, oxygen bubbling, and a mixture of redox buffers were employed to prepare doxorubicin-loaded HSA-LA nanoparticles. The nanocarrier was supposed to release the loaded doxorubicin in reductive and acidic pH media. Fourier-transform infrared spectroscopy and energy dispersive X-ray analysis indicated successful attachment of LA to HSA. The prepared nanoplatform presented improved doxorubicin loading efficiency and content and successfully released the loaded doxorubicin in the expected conditions. Protein corona study indicated that positively charged plasma proteins with molecular weights of nearly 80 kDa are absorbed to the surface of the nanoparticles. Furthermore, it showed desirable UV and storage stability, which implied its robustness and improved shelf life if applied in nanomedicine.


Assuntos
Nanopartículas , Neoplasias , Humanos , Albumina Sérica Humana , Doxorrubicina , Nanopartículas/química , Polietilenoglicóis/química , Concentração de Íons de Hidrogênio , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos
6.
Lasers Surg Med ; 54(2): 202-216, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34363230

RESUMO

BACKGROUND AND OBJECTIVE: Optogenetics has opened new insights into biomedical research with the ability to manipulate and control cellular activity using light in combination with genetically engineered photosensitive proteins. By stimulating with light, this method provides high spatiotemporal and high specificity resolution, which is in contrast to conventional pharmacological or electrical stimulation. Optogenetics was initially introduced to control neural activities but was gradually extended to other biomedical fields. STUDY DESIGN: In this paper, firstly, we summarize the current optogenetic tools stimulated by different light sources, including lasers, light-emitting diodes, and laser diodes. Second, we outline the variety of biomedical applications of optogenetics not only for neuronal circuits but also for various kinds of cells and tissues from cardiomyocytes to ganglion cells. Furthermore, we highlight the potential of this technique for treating neurological disorders, cardiac arrhythmia, visual impairment, hearing loss, and urinary bladder diseases as well as clarify the mechanisms underlying cancer progression and control of stem cell differentiation. CONCLUSION: We sought to summarize the various types of promising applications of optogenetics to treat a broad spectrum of disorders. It is conceivable to expect that optogenetics profits a growing number of patients suffering from a range of different diseases in the near future.


Assuntos
Neoplasias , Optogenética , Humanos , Lasers , Neoplasias/metabolismo , Neurônios/metabolismo , Optogenética/métodos
7.
BMC Bioinformatics ; 22(1): 549, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34758751

RESUMO

BACKGROUND: Antimicrobial peptides are promising tools to fight against ever-growing antibiotic resistance. However, despite many advantages, their toxicity to mammalian cells is a critical obstacle in clinical application and needs to be addressed. RESULTS: In this study, by using an up-to-date dataset, a machine learning model has been trained successfully to predict the toxicity of antimicrobial peptides. The comprehensive set of features of both physico-chemical and linguistic-based with local and global essences have undergone feature selection to identify key properties behind toxicity of antimicrobial peptides. After feature selection, the hybrid model showed the best performance with a recall of 0. 876 and a F1 score of 0. 849. CONCLUSIONS: The obtained model can be useful in extracting AMPs with low toxicity from AMP libraries in clinical applications. On the other hand, several properties with local nature including positions of strand forming and hydrophobic residues in final selected features show that these properties are critical definer of peptide properties and should be considered in developing models for activity prediction of peptides. The executable code is available at https://git.io/JRZaT .


Assuntos
Aprendizado de Máquina , Peptídeos , Animais , Resistência Microbiana a Medicamentos , Proteínas Citotóxicas Formadoras de Poros
8.
Adv Exp Med Biol ; 1318: 923-936, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33973220

RESUMO

The coronavirus disease 2019 (COVID-19) pandemic has been a significant concern worldwide. The pandemic has demonstrated that public health issues are not merely a health concern but also affect society as a whole. In this chapter, we address the importance of bringing together the world's scientists to find appropriate solutions for controlling and managing the COVID-19 pandemic. Interdisciplinary cooperation, through modern scientific methods, could help to handle the consequences of the pandemic and to avoid the recurrence of future pandemics.


Assuntos
COVID-19 , Pandemias , Humanos , Pandemias/prevenção & controle , Saúde Pública , SARS-CoV-2
9.
J Transl Med ; 18(1): 205, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32430070

RESUMO

The COVID-19 pandemic has become the leading societal concern. The pandemic has shown that the public health concern is not only a medical problem, but also affects society as a whole; so, it has also become the leading scientific concern. We discuss in this treatise the importance of bringing the world's scientists together to find effective solutions for controlling the pandemic. By applying novel research frameworks, interdisciplinary collaboration promises to manage the pandemic's consequences and prevent recurrences of similar pandemics.


Assuntos
Pesquisa Biomédica/organização & administração , Infecções por Coronavirus/epidemiologia , Prestação Integrada de Cuidados de Saúde/organização & administração , Emergências , Necessidades e Demandas de Serviços de Saúde , Pandemias , Pneumonia Viral/epidemiologia , Betacoronavirus/patogenicidade , Pesquisa Biomédica/métodos , COVID-19 , Infecções por Coronavirus/terapia , Infecções por Coronavirus/virologia , Prestação Integrada de Cuidados de Saúde/métodos , História do Século XXI , Humanos , Comunicação Interdisciplinar , Estudos Interdisciplinares , Pneumonia Viral/terapia , Pneumonia Viral/virologia , Saúde Pública/história , Saúde Pública/normas , SARS-CoV-2
10.
J Fluoresc ; 29(4): 827-835, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31218597

RESUMO

Considering the importance of pharmacology and the influence of drugs on biological materials, the effects of a newly designed and synthesized platin complex (2,2'-Bipyridine-3,3'-dicarboxylic acid, oxalato Platinum(II), as an antitumor drug was tested on the structure of blood carrier protein of human serum albumin (HSA) using various spectroscopic techniques including UV-visible, fluorescence, and circular dichroism at 25 and 37 °C. Results of the fluorescence measurements revealed that adding the complex caused reduction in intrinsic fluorescence emission of HSA resulted from dynamic quenching of HSA. The number of binding sites and binding constants were calculated at both temperatures of 25 and 37 °C. In addition, in order to identify the complex's binding site on HSA employing spectroscopy, the competitive studies were followed using warfarin, digitoxin and ibuprofen as site markers of Sudlow sites I, II and III. Competitive binding test results have shown that Pt(II) complex bind on the warfarin binding site (or Sudlow sites I) on HSA. Besides, a reduction in thermal stability for HSA was observed in the presence of the newly designed Pt(II) complex.


Assuntos
Compostos Organoplatínicos/síntese química , Compostos Organoplatínicos/metabolismo , Albumina Sérica Humana/metabolismo , Ligação Competitiva , Humanos , Ligação Proteica , Espectrometria de Fluorescência
11.
Neuropathology ; 39(1): 14-21, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30536911

RESUMO

Multiple sclerosis (MS) is known as the most common demyelinating disease worldwide in which previous studies have shown that stress is a risk factor for the disease's onset and progression. Nevertheless, further studies are needed to investigate the consequences of stress in MS pathology. In this study, after 5 days of exposure to psychological and physical stress as a repetitive distress modality, rats were treated with cuprizone. The demyelination degree was compared in animal groups using Luxol fast blue staining, immunohistochemical staining for myelin basic protein and transmission electron microscopy. Outcomes revealed that animals exposed to stress prior to cuprizone ingestion, elicit more intense demyelination. Continuous psychological distress has more severe effects on myelin sheath destruction in the preclinical stage.


Assuntos
Doenças Desmielinizantes/complicações , Doenças Desmielinizantes/patologia , Bainha de Mielina/ultraestrutura , Estresse Psicológico/complicações , Animais , Corpo Caloso/efeitos dos fármacos , Corpo Caloso/ultraestrutura , Cuprizona/administração & dosagem , Doenças Desmielinizantes/induzido quimicamente , Modelos Animais de Doenças , Feminino , Ratos Wistar
12.
J Enzyme Inhib Med Chem ; 34(1): 279-309, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30734608

RESUMO

Tyrosinase is a multi-copper enzyme which is widely distributed in different organisms and plays an important role in the melanogenesis and enzymatic browning. Therefore, its inhibitors can be attractive in cosmetics and medicinal industries as depigmentation agents and also in food and agriculture industries as antibrowning compounds. For this purpose, many natural, semi-synthetic and synthetic inhibitors have been developed by different screening methods to date. This review has focused on the tyrosinase inhibitors discovered from all sources and biochemically characterised in the last four decades.


Assuntos
Chalcona/farmacologia , Cumarínicos/farmacologia , Inibidores Enzimáticos/farmacologia , Flavonoides/farmacologia , Monofenol Mono-Oxigenase/antagonistas & inibidores , Resveratrol/farmacologia , Agaricales/enzimologia , Animais , Chalcona/química , Cumarínicos/química , Inibidores Enzimáticos/química , Flavonoides/química , Humanos , Monofenol Mono-Oxigenase/metabolismo , Resveratrol/química
13.
Arch Biochem Biophys ; 647: 54-66, 2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29444458

RESUMO

Altered blood-brain barrier (BBB) permeability may contribute to pathogenesis of diabetes-related central nervous system disorders. Considering the presence of glycated insulin in plasma of type 2 diabetic patients, we hypothesized that glycated insulin could induce changes in paracellular permeability in BBB. Therefore, the authors decided to study the effect of glycated insulin on paracellular permeability in a BBB model and the change induced in insulin conformation upon glycation. In this study, the structural modification was examined by fluorescence and circular dichroism spectroscopies and dynamic light scattering. Cell proliferation and production of ROS in astrocytes and HUVEC cells were analyzed by MTT and spectrofluorometric assays, respectively. Apoptosis induction was determined and confirmed by flow cytometry and western blot analyses, respectively. The permeability was measured Lucifer yellow and FITC-Dextran. According to our results, glycated insulin presented altered conformation and more exposed hydrophobic patches than insulin. Formation of oligomeric species and advanced glycated end products (AGEs) were determined. Lower cell viability, higher apoptosis, and more ROS were detected upon treatment of cells with glycated insulin. Finally, glycated insulin led to increased Lucifer yellow and FITC-dextran transportation across the BBB model which could result from ROS producing and apoptosis-inducing activities of AGE-insulin.


Assuntos
Barreira Hematoencefálica/metabolismo , Permeabilidade Capilar , Produtos Finais de Glicação Avançada/metabolismo , Insulina/análogos & derivados , Apoptose , Astrócitos/citologia , Astrócitos/metabolismo , Linhagem Celular , Proliferação de Células , Técnicas de Cocultura , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Células Endoteliais da Veia Umbilical Humana , Humanos , Insulina/química , Insulina/metabolismo , Espécies Reativas de Oxigênio/metabolismo
14.
Can J Physiol Pharmacol ; 96(12): 1276-1285, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30278151

RESUMO

The aim of this study was to examine the interaction of [Pd(2,2'-bipyridine) (morpholinedithiocarbamate)]NO3 and [Pt (2,2'-bipyridine)(morpholinedithiocarbamate)]NO3 with human serum albumin under physiological conditions by using fluorescence, absorption, and circular dichroism spectroscopic techniques. Spectroscopic analysis of the emission quenching at different temperatures demonstrated that the quenching mechanism was static quenching. From the circular dichroism results, thermal stability study, it was found that the interaction of the complexes with human serum albumin caused a conformational change of the protein reversibly. These 2 anticancer Pd and Pt complexes were activated against chronic myelogenous leukemia cell line K562, so that 50% cytotoxic concentration values of 16 and 26 µM for Pd and Pt complexes, respectively, were observed, which were much lower than that of cisplatin (154 µM). Biological activities of both Pd and Pt complexes were also assayed against selective microorganisms by the disc diffusion method. These results showed that the Pd(II) complex is antifungal agent but Pt(II) complex has antibacterial activity. Also, the interaction of both metal derivative complexes was studied by molecular docking. Complementary molecular docking results may be useful to determine the binding mechanism of human serum albumin in pharmaceutical and biophysical studies providing new insight in the novel pharmacology.


Assuntos
Antineoplásicos/farmacologia , Proteínas Sanguíneas/metabolismo , Proteínas de Transporte/metabolismo , Morfolinas/farmacologia , Compostos Organoplatínicos/farmacologia , Paládio/farmacologia , Albumina Sérica Humana/metabolismo , Linhagem Celular Tumoral , Dicroísmo Circular , Cisplatino/metabolismo , Cisplatino/farmacologia , Interações Medicamentosas/fisiologia , Humanos , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Simulação de Acoplamento Molecular , Ligação Proteica/fisiologia
15.
J Basic Microbiol ; 58(7): 609-622, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29775208

RESUMO

Petroleum, as the major energy source, is indispensable from our lives. Presence of compounds resistant to degradation can pose risks for human health and environment. Basidiomycetes have been considered as powerful candidates in biodegradation of petroleum compounds via secreting ligninolytic enzymes. In this study a wood-decaying fungus was isolated by significant degradation ability that was identified as Daedaleopsis sp. by morphological and molecular identification methods. According to GC/MS studies, incubation of heavy crude oil with Daedaleopsis sp. resulted in increased amounts of C24 compounds. Degradation of asphaltene, anthracene, and dibenzofuran by the identified fungal strain was determined to evaluate its potential in biodegradation. After 14 days of incubation, Daedaleopsis sp. could degrade 93.7% and 91.2% of anthracene and dibenzofuran, respectively, in pH 5 and 40 °C in optimized medium, as revealed by GC/FID. Notably, analysis of saturates, aromatics, resins, and asphaltenes showed a reduction of 88.7% and 38% in asphaletene and aromatic fractions. Laccase, lignin peroxidase, and manganese peroxidase activities were enhanced from 51.3, 145.2, 214.5 U ml-1 in the absence to 121.5, 231.4, and 352.5 U ml-1 in the presence of heavy crude oil, respectively. This is the first report that Daedaleopsis sp. can degrade asphaltene and dibenzofuran. Moreover, compared to the reported results of asphaltene biodegradation, this strain was the most successful. Thus, Daedaleopsis sp. could be a promising candidate for biotransformation of heavy crude oil and biodegradation of recalcitrant toxic compounds.


Assuntos
Basidiomycota/fisiologia , Biodegradação Ambiental , Petróleo/metabolismo , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Basidiomycota/classificação , Basidiomycota/isolamento & purificação , DNA Espaçador Ribossômico , Cromatografia Gasosa-Espectrometria de Massas , Concentração de Íons de Hidrogênio , Filogenia , Temperatura
16.
Arch Biochem Biophys ; 619: 35-44, 2017 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-28257787

RESUMO

Human protein disulfide isomerase (hPDI) is a key redox-regulated thiol-containing protein operating as both oxidoreductase and molecular chaperone in the endoplasmic reticulum of cells. hPDI thiol-disulfide interchange reactions lead to the adoption of two distinct red/ox conformations with different substrate preferences. hPDI also displays high binding capacity for some endogenous steroid hormones including 17 beta-estradiol (E2) and thus contributes to the regulation of their intracellular concentration, storage and actions. The primary focus of this study was to investigate the impact of E2 binding on functional activity of recombinant hPDI. Then, we examined the effect of E2 binding on structural alteration of hPDI red/ox conformations and its influence on affinity and position of interaction using experimental and computational analysis. Our results revealed that interaction of one E2 per each hPDI molecule led to the inhibition of hPDI reductase activity and conformational changes in both oxidation states. Mutually, E2-binding position were also redox-regulated with higher affinity in oxidized hPDI compare to the reduced form. The importance of histidine-256 protonation states in distinct binding preferences of E2 were also demonstrated in hPDI red/ox conformations. These findings might pave the way for better understanding of the mechanisms behind the redox-dependent hormone-binding activity of hPDI.


Assuntos
Estradiol/química , Isomerases de Dissulfetos de Proteínas/química , Clonagem Molecular , Dissulfetos/química , Estrogênios/química , Histidina/química , Humanos , Ligação de Hidrogênio , Simulação de Dinâmica Molecular , Oxirredução , Estresse Oxidativo , Oxigênio/química , Ligação Proteica , Conformação Proteica , Software , Compostos de Sulfidrila/química
17.
Arch Biochem Biophys ; 629: 8-18, 2017 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-28711358

RESUMO

Molecular dynamics (MD) at two temperatures of 300 and 340 K identified two histidine residues, His461 and His489, in the most flexible regions of firefly luciferase, a light emitting enzyme. We therefore designed four protein mutants H461D, H489K, H489D and H489M to investigate their enzyme kinetic and thermodynamic stability changes. Substitution of His461 by aspartate (H461D) decreased ATP binding affinity, reduced the melting temperature of protein by around 25 °C and shifted its optimum temperature of activity to 10 °C. In line with the common feature of psychrophilic enzymes, the MD data showed that the overall flexibility of H461D was relatively high at low temperature, probably due to a decrease in the number of salt bridges around the mutation site. On the other hand, substitution of His489 by aspartate (H489D) introduced a new salt bridge between the C-terminal and N-terminal domains and increased protein rigidity but only slightly improved its thermal stability. Similar changes were observed for H489K and, to a lesser degree, H489M mutations. Based on our results we conclude that the MD simulation-based rational substitution of histidines by salt-bridge forming residues can modulate conformational dynamics in luciferase and shift its optimal temperature activity.


Assuntos
Substituição de Aminoácidos , Histidina , Luciferases de Vaga-Lume/química , Luciferases de Vaga-Lume/metabolismo , Temperatura , Sequência de Aminoácidos , Sequência de Bases , Estabilidade Enzimática/genética , Ligação de Hidrogênio , Cinética , Luciferases de Vaga-Lume/genética , Simulação de Dinâmica Molecular , Mutação , Conformação Proteica
18.
Eur Biophys J ; 46(5): 445-459, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27928588

RESUMO

The soluble epoxide hydrolase (sEH) enzyme plays an important role in the metabolism of endogenous chemical mediators involved in the regulation of blood pressure and inflammation. Inhibition of sEH provides a new approach to the treatment of inflammation, hypertension and atherosclerosis. In this study, the binding modes and inhibition mechanisms of the new oxadiazole-based amide inhibitors of the human soluble epoxide hydrolase were investigated by molecular docking and molecular dynamics (MD) simulation followed by the MM-GBSA method to calculate the binding free energy of each inhibitor to sEH. The results obtained from the binding free energy (ΔG binding) calculation and normal mode analysis indicate that the major favorable contributors are the van der Waals and electrostatic terms, whereas the polar solvation term opposes binding. In addition, a good agreement between the calculated ΔG binding and the experimental IC50 was obtained [correlation coefficient, r 2 = 0.89 (with) and 0.87 (without) entropy]. Besides, comparison of the enthalpy changes (ΔG MM-GBSA) with entropy changes (-TΔS) indicates that binding process of all inhibitors to sEH is enthalpy-driven. Based on the ΔG binding on per residue decomposition, Asp335 and Tyr383 residues from the active site and Trp336, Leu499 and His524 residues from hydrophobic pockets contribute the most to ΔG binding. Moreover, hydrogen bond analysis reveals that Tyr383, Tyr466 and Asp335 residues have an important role in the binding to inhibitors by forming hydrogen bonds with high occupancies. Our obtained results are useful for the understanding of the sEH-inhibitor interactions and may have great importance in the design of future sEH inhibitors.


Assuntos
Amidas/química , Epóxido Hidrolases/química , Epóxido Hidrolases/metabolismo , Simulação de Acoplamento Molecular , Oxidiazóis/química , Oxidiazóis/metabolismo , Domínio Catalítico , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Epóxido Hidrolases/antagonistas & inibidores , Ligação de Hidrogênio , Simulação de Dinâmica Molecular , Oxidiazóis/farmacologia , Ligação Proteica , Solubilidade , Relação Estrutura-Atividade , Termodinâmica
19.
Bioorg Med Chem ; 25(9): 2577-2582, 2017 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-28343756

RESUMO

A panel of 22 phenols was investigated as inhibitors of the ß-class carbonic anhydrase (CAs, EC 4.2.1.1) from the fungal parasite Malassezia globosa (MgCA), a validated anti-dandruff drug target. The displayed inhibitory activities were compared to the ones previously reported against the off-target widely distributed human (h) isoforms hCA I and II. All tested phenols possessed a better efficacy in inhibiting MgCA than the clinically used sulfonamide acetazolamide, with KIs in the range of 2.5 and 65.0µM. A homology-built model of MgCA was also used for understanding the binding mode of phenols to the fungal enzyme. Indeed, a wide network of hydrogen bonds and hydrophobic interactions between the phenol and active site residues were evidenced. The OH moiety of the inhibitor was observed anchored to the zinc-coordinated water, also making hydrogen bonds with Ser48 and Asp49. The diverse substituents at the phenolic scaffold were observed to interact with different portions of the hydrophobic pocket according to their nature and position. Considering the effective MgCA inhibitory properties of phenols, beside to the rather low inhibition against the off-target hCA I and II, this class of compounds might be of considerable interest in the cosmetics field as potential anti-dandruff drugs.


Assuntos
Inibidores da Anidrase Carbônica/farmacologia , Malassezia/enzimologia , Fenóis/farmacologia , Acetazolamida/farmacologia , Anidrase Carbônica I/antagonistas & inibidores , Inibidores da Anidrase Carbônica/química , Caspa/tratamento farmacológico , Humanos , Ligação de Hidrogênio , Simulação de Acoplamento Molecular , Fenóis/química , Relação Estrutura-Atividade
20.
J Fluoresc ; 27(5): 1829-1838, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28555407

RESUMO

In the present study, biological evaluation of a new synthesized anti-cancer compound, amyl-glycine1, 10-phenanthroline Platinum nitrate (Pt(II) complex), was investigated at different temperatures by spectroscopic methods (far-UV circular dichroism (CD) and fluorescence) and modeling methods (docking and FRET). Human serum albumin (HSA), one of the vital proteins in drug delivery system in the body, was used as a target protein. The Pt(II) complex is able to quench the intrinsic fluorescence of HSA considerably. Binding and thermodynamic parameters of the interaction between the protein and the ligand were analyzed by fluorescence quenching method. The far-UV CD spectra revealed that the secondary structure of HSA did not show any noticeable change upon interaction with Pt(II) complex at both 25 and 37°C. The calculation of fluorescence resonance energy transfer (FRET) confirmed that quenching mechanism is static, and the observed distance between the donor and acceptor is 1.18 nm. Molecular docking results are in agreement with experimental data suggesting that there is one site on HSA at which Pt(II) complex binds spontaneously. Moreover, docking results together with FRET evaluation illustrated that Pt(II) complex is located near Trp214 at a distance of 1.96 nm. Our experimental and theoretical results indicated that the driving forces for Pt(II) complex interaction with HSA are hydrogen bonding and van der Waals interactions. The combination of molecular docking and spectroscopy methods suggested that use of this new Pt(II) complex as an anti-cancer agent, is an effective innovative approach in cancer chemotherapy providing a better understanding of effects of new designed drugs.


Assuntos
Antineoplásicos/farmacologia , Complexos de Coordenação/farmacologia , Glicina/análogos & derivados , Glicina/farmacologia , Modelos Moleculares , Fenantrolinas/farmacologia , Albumina Sérica Humana/química , Antineoplásicos/química , Sítios de Ligação , Complexos de Coordenação/química , Glicina/química , Humanos , Simulação de Acoplamento Molecular , Fenantrolinas/química , Ligação Proteica , Conformação Proteica , Albumina Sérica Humana/metabolismo , Espectrometria de Fluorescência , Termodinâmica
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