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1.
Dokl Biochem Biophys ; 486(1): 220-223, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31367826

RESUMO

Cardiolipin (CL) plays a central role in lipid peroxidation (LPO) of the mitochondrial inner membrane due to higher content of unsaturated fatty acids in CL in comparison with the other phospholipids. CL oxidation plays an important role in the regulation of various intracellular signaling pathways and its excessive oxidation contributes to the development of various pathologies and, possibly, participates in the aging process. Mitochondria-targeted antioxidants containing triphenylphosphonium (TPP+) effectively protect CL from oxidation. It is assumed that fluorescent probes on the basis of the C11-BODIPY fluorophore sensitive to LPO and containing TPP+ can selectively register CL oxidation. To test this possibility, we carried out a molecular dynamic simulation of such probes in a model mitochondrial membrane. It is shown that the probes are located in the membrane at the same depth as the unsaturated bonds in CL molecules sensitive to oxidation. Increasing the length of the linker that binds the fluorophore and TPP+ residue ha little effect on the position of the probe in the membrane. This indicates the possibility of modifying the linker to increase the selectivity of the probes to CL.


Assuntos
Corantes Fluorescentes/metabolismo , Peroxidação de Lipídeos , Membranas Mitocondriais/metabolismo , Simulação de Dinâmica Molecular , Compostos de Boro/metabolismo
2.
Eur J Histochem ; 63(3)2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31455073

RESUMO

RNA interference is a powerful approach to understand gene function both for therapeutic and experimental purposes. Since the lack of knowledge in the gene silencing of various hepatic cell lines, this work was aimed to compare two transfection agents, the liposome-based Lipofectamine™ RNAiMAX and the HepG2-specific, polymer-based GenMute™, in two cellular models of human hepatoma, HepG2 and Huh7.5. In the first part, we assessed transfection efficiency of a fluorescent Cy3-labeled negative control siRNA by cell imaging analysis; we found that cells treated with GenMute present a higher uptake of the fluorescent negative control siRNA when compared to Lipofectamine RNAiMAX-transfected cells, both in HepG2 and in Huh7.5 cells. In the second part, we evaluated GAPDH silencing with the two transfection reagents by RT-PCR similar GAPDH mRNA expression after each transfection treatment. Finally, we measured cell viability by the MTT assay, observing that cells transfected with GenMute have higher viability with respect to Lipofectamine RNAiMAX-administered cells. These results suggest that GenMute reagent might be considered the most suitable transfection agent for hepatic gene silencing.


Assuntos
Técnicas de Transferência de Genes , Lipídeos/química , Polímeros/química , RNA Interferente Pequeno/genética , Transfecção/métodos , Sequência de Bases , Carbocianinas/química , Carbocianinas/metabolismo , Carcinoma Hepatocelular/genética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Inativação Gênica , Gliceraldeído-3-Fosfato Desidrogenases/genética , Humanos , Metabolismo dos Lipídeos , Lipídeos/toxicidade , Lipossomos/química , Lipossomos/metabolismo , Lipossomos/toxicidade , Neoplasias Hepáticas/genética , Polímeros/metabolismo , Polímeros/toxicidade , Interferência de RNA
3.
Phys Chem Chem Phys ; 21(28): 15779-15786, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31282523

RESUMO

Small-molecule fluorescent probes having optimized optical properties, such as high photostability and brightness, local microenvironment sensitivity and specific subcellular localizations, are increasingly available. Although the basis for designing efficient fluorophores for bioimaging applications is well established, implementing an improvement in a given photophysical characteristic always tends to compromise another optical property. This problem has enormous consequences for in vivo imaging, where ensuring a specific localization and precise control of the probe response is challenging. Herein we discuss a fluorescent probe, CC334, as a case study of the chromenylium-cyanine family that commonly exhibits highly complex photophysical schemes and highly interfered bioanalytical responses. By an exhaustive and concise analysis of the CC334 optical responses including detailed spectroscopic calibrations, steady-state microenvironment effects, ultrafast photophysics analysis and computational studies, we elucidate a new strategy to apply the probe in the singlet oxygen reactive oxygen species (1O2-ROS) monitoring using in vitro and in vivo models. The probe provides a new avenue for designing fluorescent probes to understand the dynamic behavior of subcellular environments.


Assuntos
Benzopiranos/química , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Cobalto/química , Ferrocianetos/química , Quinolinas/química , Espécies Reativas de Oxigênio/química , Análise Espectral
4.
Chem Commun (Camb) ; 55(58): 8402-8405, 2019 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-31257385

RESUMO

A proof-of-principle for the application of hemi-indigo derivatives as RNA binders with photocontrollable fluorescence is presented. The photoswitch binds to the human immunodeficiency virus type 1 (HIV-1) RNA with a significant light-up effect. The fluorescence of the RNA-bound ligand can be reversibly switched ON and OFF by light without destroying the ligand-RNA associates.


Assuntos
Corantes Fluorescentes/metabolismo , HIV-1/genética , Indóis/metabolismo , RNA/metabolismo , Fluorescência , Corantes Fluorescentes/química , Corantes Fluorescentes/efeitos da radiação , Indóis/química , Indóis/efeitos da radiação , Ligantes , Luz , Estudo de Prova de Conceito , RNA/genética , Elementos de Resposta , Estereoisomerismo
5.
Nat Commun ; 10(1): 2745, 2019 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-31227705

RESUMO

Small molecule probes are indispensable tools to explore diverse cellular events. However, finding a specific probe of a target remains a high challenge. Here we report the discovery of Fast-TRFS, a specific and superfast fluorogenic probe of mammalian thioredoxin reductase, a ubiquitous enzyme involved in regulation of diverse cellular redox signaling pathways. By systematically examining the processes of fluorophore release and reduction of cyclic disulfides/diselenides by the enzyme, structural factors that determine the response rate and specificity of the probe are disclosed. Mechanistic studies reveal that the fluorescence signal is switched on by a simple reduction of the disulfide bond within the probe, which is in stark contrast to the sensing mechanism of published probes. The favorable properties of Fast-TRFS enable development of a high-throughput screening assay to discover inhibitors of thioredoxin reductase by using crude tissue extracts as a source of the enzyme.


Assuntos
Descoberta de Drogas/métodos , Corantes Fluorescentes/química , Imagem Molecular/métodos , Sondas Moleculares/química , Tiorredoxina Redutase 1/metabolismo , Animais , Produtos Biológicos/farmacologia , Misturas Complexas , Dissulfetos/química , Corantes Fluorescentes/metabolismo , Células HeLa , Ensaios de Triagem em Larga Escala/métodos , Humanos , Microscopia Intravital/métodos , Microscopia de Fluorescência/métodos , Sondas Moleculares/metabolismo , Oxirredução , RNA Interferente Pequeno/metabolismo , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , Tiorredoxina Redutase 1/antagonistas & inibidores , Tiorredoxina Redutase 1/genética
6.
Chem Commun (Camb) ; 55(54): 7852-7855, 2019 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-31215553
7.
Chem Commun (Camb) ; 55(56): 8122-8125, 2019 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-31237279

RESUMO

Pi-class glutathione S-transferase (GSTP1) is a molecular marker enzyme whose expression level is altered in various malignant tumour tissues. Herein, we report the first highly selective fluorogenic GSTP1 substrate, Ps-TG, and its membrane-permeable derivative Ps-TAc, for specific visualization of intracellular GSTP1 activity in cancer cells or epigenetically regulated GSTP1 expression.


Assuntos
Epigênese Genética , Corantes Fluorescentes/metabolismo , Glutationa S-Transferase pi/metabolismo , Glutationa/metabolismo , Humanos , Células MCF-7 , Espectrometria de Fluorescência , Especificidade por Substrato
8.
Eur J Med Chem ; 177: 291-301, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31158745

RESUMO

Based on our previous research on the fluorinated phenylquinoxaline scaffold, in this study, different positions of N,N-dimethyl amino group, and alkyl linkers with various lengths were introduced into this scaffold to regulate their lipophilicity and binding affinity to Tau. Four novel 99mTc/Re complexes with diethyl iminodiacetate chelator were synthesized and evaluated as Tau imaging tracers in the brain of Alzheimer's disease. Their specific binding to neurofibrillary tangles was verified by in vitro fluorescence staining and further confirmed by the results of immunofluorescence staining on the same brain sections from AD patient and Tg-tau mice. From in vitro binding assay using recombinant Tau aggregates, complex 4.2 with 6-N(CH3)2 and longer carbon chain (n = 4) displayed the highest affinity (Kd = 59.95 nM). [99mTc]4.2 was achieved by the ligand exchange reaction between dicarboxylic precursor and [99mTc(CO)3(H2O)3]+ intermediate with radiochemical yield over 45%. Ex vivo biodistribution studies on normal ICR mice revealed that [99mTc]4.2 exhibited moderate initial brain uptake (0.61% ID/g) and more structure optimizations are still required to improve the blood-brain barrier permeability.


Assuntos
Doença de Alzheimer/diagnóstico , Complexos de Coordenação/química , Corantes Fluorescentes/química , Compostos de Organotecnécio/química , Quinoxalinas/química , Proteínas tau/metabolismo , Idoso de 80 Anos ou mais , Peptídeos beta-Amiloides/metabolismo , Animais , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Quelantes/síntese química , Quelantes/química , Quelantes/metabolismo , Complexos de Coordenação/síntese química , Complexos de Coordenação/metabolismo , Feminino , Fluorescência , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/metabolismo , Humanos , Iminoácidos/síntese química , Iminoácidos/química , Iminoácidos/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICR , Estrutura Molecular , Emaranhados Neurofibrilares/metabolismo , Emaranhados Neurofibrilares/patologia , Compostos de Organotecnécio/síntese química , Compostos de Organotecnécio/metabolismo , Fragmentos de Peptídeos/metabolismo , Quinoxalinas/síntese química , Quinoxalinas/metabolismo , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/metabolismo , Rênio/química , Distribuição Tecidual
9.
Talanta ; 202: 152-158, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31171163

RESUMO

Colorectal cancer (CRC) is the third most commonly diagnosed cancer in the world, which can lead to considerably high mortality rate. It was reported that the prognosis is extremely poor and survival is often measured in months once CRC metastases become clinically evident. Therefore, the development of effective approach for metastatic CRC cells detection and imaging may potentially be significant and helpful for CRC prognosis and treatment. Therefore, we proposed a sensitive and specific approach for high-metastatic CRC LoVo cells detection and imaging by using terminal deoxynucleotidyl transferase (TdT)-initiated molecule beacons (MBs) arrayed fluorescent aptamer probes (denoted as TMAP). In this approach, the aptamer W3 targeting high-metastatic CRC LoVo cells was elongated to form W3-poly A at the 3'-hydroxyl terminus with repeated A bases in the presence of TdT and dATP. The MBs designed with poly T sequence in the loop were then hybridized with the poly A in the aptamer W3. The TMAP was easily constructed without the need of aptamer modification. It was demonstrated that this approach could specifically detect and image the high-metastatic CRC LoVo cells from the mixture of high-metastatic CRC LoVo cells and non-metastatic HCT-8 cells. Compared with 6-carboxyfluorescein (6-FAM) labeled aptamer W3, the TMAP was demonstrated to have a much stronger fluorescence signal on the target cells, realizing a 4-fold increase in signal-to-background ratio (SBR). Determination by flow cytometry allowed for detection of as low as 23 CRC LoVo cells in 200 µL cell culture medium. The high sensitivity and the capability for using in complicate biological samples imply that this approach holds considerable potential for metastatic CRC detection and therapy.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais , Neoplasias Colorretais/diagnóstico por imagem , DNA Nucleotidilexotransferase/química , Corantes Fluorescentes/química , Neoplasias Colorretais/metabolismo , DNA Nucleotidilexotransferase/metabolismo , Corantes Fluorescentes/metabolismo , Humanos , Espectrometria de Fluorescência , Células Tumorais Cultivadas
10.
J Biochem ; 166(3): 205-212, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31251348

RESUMO

Signal enhancing systems have been introduced to enable detection of cell surface antigens by flow cytometry. Cell surface antigens are important targets that describe the function and lineage of cells. Although flow cytometry is an effective tool for analysing cell surface antigens, this technique has poor sensitivity, which prohibits the detection of many important antigens on cell membranes. Thus, signal amplification is essential for developing practical tools for evaluating cell surface antigens by flow cytometry. Using a bright fluorophore or fluorescent polymer incorporated into antibodies is a straightforward strategy to improve flow cytometry sensitivity but may affect the functional characteristics of the labelled antibody. In contrast, enzymatic signal amplification is a more practical and efficient strategy to improve sensitivity that should not affect antibody activity. Although enzymatic signal amplification still has a number of drawbacks, this approach is a promising strategy to analyse cell surface antigens.


Assuntos
Antígenos de Superfície/análise , Citometria de Fluxo , Anticorpos/química , Anticorpos/imunologia , Anticorpos/metabolismo , Antígenos de Superfície/imunologia , Antígenos de Superfície/metabolismo , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Humanos , Polímeros/química , Polímeros/metabolismo
11.
Chemistry ; 25(48): 11180-11192, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31215686

RESUMO

The plasma membrane regulates the transport of molecules into the cell. Small hydrophobic molecules can diffuse directly across the lipid bilayer. However, larger molecules require specific transporters for their entry into the cell. Regulating the cellular entry of small molecules and proteins is a challenging task. The introduction of halogen, particularly iodine, to small molecules and proteins is emerging to be a promising strategy to improve the cellular uptake. Recent studies reveal that a simple substitution of hydrogen atom with iodine not only increases the cellular uptake, but also regulates the membrane transport. The strong halogen-bond-forming ability of iodine atoms plays a crucial role in the transport and the introduction of iodine may provide an efficient strategy for studying membrane activity and cellular functions and improving the delivery of therapeutic agents. This Concept article does not provide a comprehensive picture of membrane transport but highlights halogen-substitution as a novel strategy for understanding and regulating the cell-membrane traffic.


Assuntos
Membrana Celular/metabolismo , Iodo/metabolismo , Biocatálise , Transporte Biológico , Permeabilidade da Membrana Celular , Corantes Fluorescentes/metabolismo , Células HeLa , Células Hep G2 , Humanos , Interações Hidrofóbicas e Hidrofílicas , Iodeto Peroxidase/metabolismo , Modelos Moleculares , Naftalimidas/metabolismo , Ligação Proteica , Conformação Proteica , Hormônios Tireóideos/metabolismo
12.
Inorg Chem ; 58(13): 8587-8595, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31117633

RESUMO

A new N,O-based BODIPY ligand was synthesized and further utilized to develop highly fluorescent and photostable Ru(II), Rh(III), and Ir(III) metal complexes. The complexes were fully characterized by different analytical techniques including single-crystal XRD studies. The photostabilities and live cell imaging capabilities of the complexes were investigated via confocal microscopy. The complexes localized specifically in the mitochondria of live cells and showed negligible cytotoxicities at a concentration used for imaging purposes. They also exhibited high photostabilities, with fluorescence intensities remaining above 50% after 1800 scans.


Assuntos
Compostos de Boro/metabolismo , Complexos de Coordenação/metabolismo , Corantes Fluorescentes/metabolismo , Mitocôndrias/metabolismo , Transporte Biológico , Compostos de Boro/síntese química , Compostos de Boro/efeitos da radiação , Compostos de Boro/toxicidade , Complexos de Coordenação/síntese química , Complexos de Coordenação/efeitos da radiação , Complexos de Coordenação/toxicidade , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/efeitos da radiação , Corantes Fluorescentes/toxicidade , Células HeLa , Humanos , Irídio/química , Ligantes , Microscopia Confocal , Fotodegradação , Ródio/química , Rutênio/química
13.
Chem Commun (Camb) ; 55(48): 6902-6905, 2019 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-31134979

RESUMO

Based on a BODIPY molecular rotor and a zinc-dipicolylamine receptor, we designed a fluorogenic probe for the detection of apoptosis. Being poorly emissive in solution and with healthy cells, it selectively binds phosphatidylserine of early apoptotic cells and internalizes into late apoptotic cells, lighting up its green fluorescence.


Assuntos
Apoptose , Compostos de Boro/química , Corantes Fluorescentes/química , Compostos Organometálicos/análise , Ácidos Picolínicos/análise , Biomarcadores Tumorais/análise , Compostos de Boro/metabolismo , Linhagem Celular , Membrana Celular/metabolismo , Corantes Fluorescentes/metabolismo , Células HeLa , Humanos , Fosfatidilserinas/química , Fosfatidilserinas/metabolismo
14.
Aquat Toxicol ; 212: 88-97, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31077970

RESUMO

Ionocytes are specialized cells in the epidermis of embryonic zebrafish (Danio rerio) that play important roles in ion homeostasis and have functional similarities to mammalian renal cells. Here, we examined whether these cells might also share another functional similarity with renal cells, which is the presence of efflux transporter activities useful for elimination of toxic small molecules. Xenobiotic transporters (XTs), including the ATP-Binding Cassette (ABC) family, are a major defense mechanism against diffusible toxic molecules in aquatic embryos, including zebrafish, but their activity in the ionocytes has not previously been studied. Using fluorescent small molecule substrates of XT, we observed that specific populations of ionocytes uptake and efflux fluorescent small molecules in a manner consistent with active transport. We specifically identified a P-gp/ABCB1 inhibitor-sensitive efflux activity in the H+-ATPase-rich (HR) ionocytes, and show that these cells exhibit enriched expression of the ABCB gene, abcb5. The results extend our understanding of the functional significance of zebrafish ionocytes and indicate that these cells could play an important role in protection of the fish embryo from harmful small molecules.


Assuntos
Embrião não Mamífero/citologia , Embrião não Mamífero/metabolismo , Xenobióticos/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/metabolismo , Animais , Ânions , Transporte Biológico , Epiderme/efeitos dos fármacos , Corantes Fluorescentes/metabolismo , Mitocôndrias/metabolismo , ATPases Translocadoras de Prótons/metabolismo , Proteínas de Peixe-Zebra/genética
15.
Nat Methods ; 16(6): 533-544, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31110282

RESUMO

Fluorescence in situ hybridization (FISH) reveals the abundance and positioning of nucleic acid sequences in fixed samples. Despite recent advances in multiplexed amplification of FISH signals, it remains challenging to achieve high levels of simultaneous amplification and sequential detection with high sampling efficiency and simple workflows. Here we introduce signal amplification by exchange reaction (SABER), which endows oligonucleotide-based FISH probes with long, single-stranded DNA concatemers that aggregate a multitude of short complementary fluorescent imager strands. We show that SABER amplified RNA and DNA FISH signals (5- to 450-fold) in fixed cells and tissues. We also applied 17 orthogonal amplifiers against chromosomal targets simultaneously and detected mRNAs with high efficiency. We then used 10-plex SABER-FISH to identify in vivo introduced enhancers with cell-type-specific activity in the mouse retina. SABER represents a simple and versatile molecular toolkit for rapid and cost-effective multiplexed imaging of nucleic acid targets.


Assuntos
DNA/análise , Corantes Fluorescentes/metabolismo , Hibridização in Situ Fluorescente/métodos , Oligonucleotídeos/química , Imagem Óptica/métodos , RNA/análise , Retina/metabolismo , Animais , Células Cultivadas , DNA/genética , DNA de Cadeia Simples/química , Humanos , Camundongos , RNA/genética , Retina/diagnóstico por imagem
16.
Chem Commun (Camb) ; 55(39): 5615-5618, 2019 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-31025683

RESUMO

A selenium-containing FR/NIR AIE luminogen with efficient solid-state emission is reported. Its AIE dots exhibit high brightness, large Stokes shift, good biocompatibility and satisfactory photostability, making them the first selenium-containing FR/NIR nanoprobes with AIE characteristics for in vivo bioimaging applications with high contrast and a high penetration depth.


Assuntos
Corantes Fluorescentes/química , Imagem Óptica , Animais , Encéfalo/diagnóstico por imagem , Meios de Contraste/síntese química , Meios de Contraste/química , Meios de Contraste/metabolismo , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/metabolismo , Linfonodos/diagnóstico por imagem , Camundongos , Nanopartículas/química , Neoplasias/diagnóstico por imagem , Selênio/química , Espectroscopia de Luz Próxima ao Infravermelho , Distribuição Tecidual
17.
Prep Biochem Biotechnol ; 49(7): 727-734, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31017519

RESUMO

The accurate estimation of kinetic parameters is of fundamental importance for biochemical studies for research and industry. In this paper, we demonstrate the application of a modular microfluidic system for execution of enzyme assays that allow determining the kinetic parameters of the enzymatic reactions such as Vmax - the maximum rate of reaction and KM - the Michaelis constant. For experiments, the fluorogenic carbonate as a probe for a rapid determination of the kinetic parameters of hydrolases, such as lipases and esterases, was used. The microfluidic system together with the method described yields the kinetic constants calculated from the concentration of enzymatic product changes via a Michaelis-Menten model using the Lambert function W(x). This modular microfluidic system was validated on three selected enzymes (hydrolases).


Assuntos
Ensaios Enzimáticos/instrumentação , Esterases/metabolismo , Dispositivos Lab-On-A-Chip , Lipase/metabolismo , Carbonatos/análise , Carbonatos/metabolismo , Desenho de Equipamento , Esterases/análise , Fluorescência , Corantes Fluorescentes/análise , Corantes Fluorescentes/metabolismo , Cinética , Lipase/análise
18.
Appl Microbiol Biotechnol ; 103(11): 4585-4593, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30963206

RESUMO

Beer yeast-modified fluorescent carbon dots were synthesized via a one-step strategy for photoinduced bactericidal functions and bio-imaging in bacterial viability assessment. The proposed carbon dots (CDs) were used as an visible light-triggered antibacterial material, and the antimicrobial activities of the CDs against Gram-negative model bacterial species (Escherichia coli) were evaluated under conditions of varying other experimental parameters including CDs concentrations and treatment times. The result showed that the CDs have excellent antibacterial performance of bactericidal effect within 120 min of under visible-light irradiation. And the bactericidal efficiency increased with the increasing concentration of CDs and visible-light illumination time. Moreover, the CDs with high quantum yield (21%) possess highly negative zeta potential (- 41.7 mV) and low cytotoxicity, the CDs could serve as an efficient dye for bacterial viability evaluation, they could selectively stain dead E. coli rather than live ones, which make dead E. coli be viewed with multicolor fluorescence under different excitation wavelengths.


Assuntos
Antibacterianos/metabolismo , Escherichia coli/efeitos dos fármacos , Corantes Fluorescentes/metabolismo , Viabilidade Microbiana/efeitos dos fármacos , Fármacos Fotossensibilizantes/metabolismo , Saccharomyces cerevisiae/metabolismo , Coloração e Rotulagem/métodos , Cerveja/microbiologia , Carbono/metabolismo
19.
Chemphyschem ; 20(11): 1456-1466, 2019 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-30945450

RESUMO

The molecular behaviors of proteins under crowding conditions are crucial for understanding the protein actions in intracellular environments. Under a crowded environment, the distance between protein molecules is almost the same size as the molecular level, thus, both the excluded volume effect and short ranged soft chemical interaction on protein surface could induce the complicated influence on the protein behavior cooperatively. Recently, various kinds of analytical approaches from macroscopic to microscopic aspects have been made to evaluate the crowding effect. The method, however, has not been established to evaluate the surface specific interactions on protein surface. In this study, the analytical method to evaluate the crowding effect has been suggested by using a charge-transfer fluorescence probe, ANS. By employing the unique property of ANS attaching to charged residues on the surface of lysozyme, the crowding effect was focused, while the case was compared as a reference, in which ANS is confined in hydrophobic pockets of BSA. Consequently, the surface specific changes of fluorescence spectra were readily observed under the crowded environment, whereas the fluorescence spectra of ANS in protein inside did not change. This result suggests the fluorescence spectra of ANS binding to protein surface have the capability to estimate the crowding effect of proteins.


Assuntos
Naftalenossulfonato de Anilina/química , Corantes Fluorescentes/química , Muramidase/química , Soroalbumina Bovina/química , Naftalenossulfonato de Anilina/metabolismo , Animais , Bovinos , Galinhas , Fluorescência , Corantes Fluorescentes/metabolismo , Muramidase/metabolismo , Ligação Proteica , Soroalbumina Bovina/metabolismo , Espectrometria de Fluorescência , Eletricidade Estática , Viscosidade
20.
Nat Chem Biol ; 15(5): 472-479, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30992561

RESUMO

Several turn-on RNA aptamers that activate small-molecule fluorophores have been selected in vitro. Among these, the ~30 nucleotide Mango-III is notable because it binds the thiazole orange derivative TO1-Biotin with high affinity and fluoresces brightly (quantum yield 0.55). Uniquely among related aptamers, Mango-III exhibits biphasic thermal melting, characteristic of molecules with tertiary structure. We report crystal structures of TO1-Biotin complexes of Mango-III, a structure-guided mutant Mango-III(A10U), and a functionally reselected mutant iMango-III. The structures reveal a globular architecture arising from an unprecedented pseudoknot-like connectivity between a G-quadruplex and an embedded non-canonical duplex. The fluorophore is restrained into a planar conformation by the G-quadruplex, a lone, long-range trans Watson-Crick pair (whose A10U mutation increases quantum yield to 0.66), and a pyrimidine perpendicular to the nucleobase planes of those motifs. The improved iMango-III and Mango-III(A10U) fluoresce ~50% brighter than enhanced green fluorescent protein, making them suitable tags for live cell RNA visualization.


Assuntos
Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/metabolismo , Corantes Fluorescentes/química , Corantes Fluorescentes/metabolismo , Aptâmeros de Nucleotídeos/genética , Mutação , Conformação de Ácido Nucleico
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