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1.
Phys Chem Chem Phys ; 22(9): 4875-4879, 2020 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-32072999

RESUMO

Structural studies on proteins directly in their native environment are required for a comprehensive understanding of their function. Electron paramagnetic resonance (EPR) spectroscopy and in particular double electron-electron resonance (DEER) distance determination are suited to investigate spin-labeled proteins directly in the cell. The combination of intracellular bioorthogonal labeling with in-cell DEER measurements does not require additional purification or delivery steps of spin-labeled protein to the cells. In this study, we express eGFP in E. coli and use copper-catalyzed azide-alkyne cycloaddition (CuAAC) for the site-directed spin labeling of the protein in vivo, followed by in-cell EPR distance determination. Inter-spin distance measurements of spin-labeled eGFP agree with in vitro measurements and calculations based on the rotamer library of the spin label.


Assuntos
Espectroscopia de Ressonância de Spin Eletrônica , Escherichia coli/metabolismo , Proteínas de Fluorescência Verde/química , Alquinos/química , Azidas/química , Catálise , Cobre/química , Reação de Cicloadição , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Óxidos de Nitrogênio/química , Marcadores de Spin
2.
Chem Commun (Camb) ; 56(15): 2344-2347, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-31993612

RESUMO

In our report, we found a distinct difference in azido sugar metabolic rate between neural stem cells and fibroblasts, which can be used for selective removal of fibroblasts from neural stem cell mixtures. Chemically induced neural stem cells (ciNSCs) serve as a highly valuable source of NSCs. Incompletely induced fibroblasts could interfere with ciNSC differentiation and become tumorigenic. Herein, we applied our method for the decontamination of ciNSCs and it exhibited excellent selectivity for ciNSCs. The results demonstrate that the ciNSC population can be efficiently purified to 98.1%. As far as we know, this is the highest purity obtained so far. We envision that, in the future, our method could be used as a safe, effective, and chemically-defined tool for decontaminating ciNSCs in both fundamental research and clinical stem cell therapy.


Assuntos
Azidas/metabolismo , Fibroblastos/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Neurais/metabolismo , Açúcares/metabolismo , Células 3T3 , Animais , Azidas/química , Proliferação de Células , Fibroblastos/química , Células-Tronco Pluripotentes Induzidas/química , Camundongos , Células-Tronco Neurais/química , Açúcares/química
3.
Chem Commun (Camb) ; 56(13): 1988-1991, 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-31960852

RESUMO

Kinugasa reactions hold potential for bioorthogonal chemistry in that the reagents can be biocompatible. Unlike other bioorthogonal reaction products, ß-lactams are potentially reactive, which can be useful for synthesizing new biomaterials. A limiting factor for applications consists of slow reaction rates. Herein, we report an optimized aqueous copper(i)-catalyzed alkyne-nitrone cycloaddition involving rearrangement (CuANCR) with rate accelerations made possible by the use of surfactant micelles. We have investigated the factors that accelerate the aqueous CuANCR reaction and demonstrate enhanced modification of a model membrane-associated peptide. We discovered that lipids/surfactants and alkyne structure have a significant impact on the reaction rate, with biological lipids and electron-poor alkynes showing greater reactivity. These new findings have implications for the use of CuANCR for modifying integral membrane proteins as well as live cell labelling and other bioorthogonal applications.


Assuntos
Reação de Cicloadição/métodos , Lipídeos/química , Tensoativos/química , Água/química , Alquinos/química , Azidas/química , Catálise , Cobre/química , Proteínas de Membrana/química
4.
Chem Commun (Camb) ; 55(87): 13093-13095, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31612161

RESUMO

Ubiquitin monomers functionalized with an azide or multiple alkynes were utilized for the assembly of branched ubiquitin oligomers (K6/K11, K11/K48, K11/K63, K6/K11/K48) by click chemistry. The oligomers resist deubiquitylase-catalysed hydrolysis and exhibit stability in eukaryotic cell lysates.


Assuntos
Ubiquitina/biossíntese , Alquinos/química , Azidas/química , Biocatálise , Química Click , Enzimas Desubiquitinantes/metabolismo , Células Eucarióticas/metabolismo , Humanos , Hidrólise , Ubiquitina/química , Ubiquitina/metabolismo , Ubiquitinação
5.
J Chem Phys ; 151(14): 144706, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31615228

RESUMO

Quantum dot (QD) biological imaging and sensing applications often require surface modification with single-stranded deoxyribonucleic acid (ssDNA) oligonucleotides. Furthermore, ssDNA conjugation can be leveraged for precision QD templating via higher-order DNA nanostructures to exploit emergent behaviors in photonic applications. Use of ssDNA-QDs across these platforms requires compact, controlled conjugation that engenders QD stability over a wide pH range and in solutions of high ionic strength. However, current ssDNA-QD conjugation approaches suffer from limitations, such as the requirement for thick coatings, low control over ssDNA labeling density, requirement of large amounts of ssDNA, or low colloidal or photostability, restraining implementation in many applications. Here, we combine thin, multidentate, phytochelatin-3 (PC3) QD passivation techniques with strain-promoted copper-free alkyne-azide click chemistry to yield functional ssDNA-QDs with high stability. This process was broadly applicable across QD sizes (i.e., λem = 540, 560, 600 nm), ssDNA lengths (i.e., 10-16 base pairs, bps), and sequences (poly thymine, mixed bps). The resulting compact ssDNA-QDs displayed a fluorescence quenching efficiency of up to 89% by hybridization with complementary ssDNA-AuNPs. Furthermore, ssDNA-QDs were successfully incorporated with higher-order DNA origami nanostructure templates. Thus, this approach, combining PC3 passivation with click chemistry, generates ssDNA-PC3-QDs that enable emergent QD properties in DNA-based devices and applications.


Assuntos
DNA de Cadeia Simples/química , Nanocompostos/química , Pontos Quânticos/química , Alquinos/química , Azidas/química , Compostos de Cádmio/química , Química Click , Fluorescência , Ouro/química , Nanopartículas Metálicas/química , Hibridização de Ácido Nucleico , Oligodesoxirribonucleotídeos/química , Fitoquelatinas/química , Poli T/química , Compostos de Selênio/química , Sulfetos/química , Propriedades de Superfície , Compostos de Zinco/química
6.
Molecules ; 24(19)2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31597251

RESUMO

1-Amino-2-nitroguanidine (ANQ) is a high-energy nitrogen-rich compound with good detonation properties and low sensitivities. ANQ has only a central carbon atom with three small groups around it, including an amino, a hydrazine and a nitroxyl group. Though the molecular structure of ANQ is very simple, its reactivity is surprisingly abundant. ANQ can undergo various reactions, including reduction reaction, acylation reaction, salification reaction, coordination reaction, aldimine condensation reaction, cyclization reaction and azide reaction. Many new energetic compounds were purposely obtained through these reactions. These reactions were systematically summarized in this review, and detonation properties of some energetic compounds were compared. In the field of energetic materials, ANQ and some derivatives exhibit good application prospects.


Assuntos
Guanidinas/química , Azidas/química , Ciclização , Estrutura Molecular , Oxirredução
7.
PLoS Biol ; 17(10): e3000475, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31584943

RESUMO

The Toxoplasma gondii inner membrane complex (IMC) is an important organelle involved in parasite motility and replication. The IMC resides beneath the parasite's plasma membrane and is composed of both membrane and cytoskeletal components. Although the protein composition of the IMC is becoming better understood, the protein-protein associations that enable proper functioning of the organelle remain largely unknown. Determining protein interactions in the IMC cytoskeletal network is particularly challenging, as disrupting the cytoskeleton requires conditions that disrupt protein complexes. To circumvent this problem, we demonstrate the application of a photoreactive unnatural amino acid (UAA) crosslinking system to capture protein interactions in the native intracellular environment. In addition to identifying binding partners, the UAA approach maps the binding interface of the bait protein used for crosslinking, providing structural information of the interacting proteins. We apply this technology to the essential IMC protein ILP1 and demonstrate that distinct regions of its C-terminal coiled-coil domain crosslink to the alveolins IMC3 and IMC6, as well as IMC27. We also show that the IMC3 C-terminal domain and the IMC6 N-terminal domain are necessary for binding to ILP1, further mapping interactions between ILP1 and the cytoskeleton. Together, this study develops a new approach to study protein-protein interactions in Toxoplasma and provides the first insight into the architecture of the cytoskeletal network of the apicomplexan IMC.


Assuntos
Azidas/química , Reagentes para Ligações Cruzadas/química , Proteínas do Citoesqueleto/química , Citoesqueleto/metabolismo , Membranas Intracelulares/metabolismo , Fenilalanina/análogos & derivados , Proteínas de Protozoários/química , Toxoplasma/metabolismo , Membrana Celular/genética , Membrana Celular/metabolismo , Membrana Celular/ultraestrutura , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Citoesqueleto/genética , Citoesqueleto/ultraestrutura , Expressão Gênica , Membranas Intracelulares/ultraestrutura , Fenilalanina/química , Processos Fotoquímicos , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Mapeamento de Interação de Proteínas/métodos , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Toxoplasma/genética , Toxoplasma/ultraestrutura , Raios Ultravioleta
8.
Molecules ; 24(19)2019 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-31569519

RESUMO

An efficient approach for the synthesis of phosphorylated isoindoline fused with triazoles via Zn(OTf)2-catalyzed cascade cyclization of easily prepared ortho-propynol benzyl azides and diarylphosphine oxides is developed. The transformation occurred smoothly in moderate to excellent yields and tolerated various propargylic alcohol substrates.


Assuntos
Azidas/química , Isoindóis/química , Triazóis/química , Zinco/química , Alquinos/química , Catálise , Ciclização , Estrutura Molecular , Fosforilação , Propanóis/química
9.
Comput Biol Chem ; 83: 107124, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31563021

RESUMO

We have recently explored novel class of potentially anti-breast cancer active enamidines in which four molecules 4a-c and 4h showed higher anticancer activity compared to standard drug doxorubicin. As a part of extension of this work, we have further evaluated in silico cheminformatic studies on bioactivity prediction of synthesized series of enamidines using mole information. The normal cell line study of four lead compounds 4a-c and 4h against African green monkey kidney vero strain further revealed that the compounds complemented good selectivity in inhibition of cancer cells. The in silico bioactivity and molecular docking studies also revealed that the compounds have significant interactions with the drug targets. The results reveal that enamidine moieties are vital for anti-breast cancer activity as they possess excellent drug-like characteristics, being potentially good inhibitors of cyclin dependent kinases7 (CDK7).


Assuntos
Aminas/farmacologia , Antineoplásicos/farmacologia , Azidas/farmacologia , Neoplasias da Mama/tratamento farmacológico , Simulação por Computador , Quinases Ciclina-Dependentes/antagonistas & inibidores , Pargilina/análogos & derivados , Inibidores de Proteínas Quinases/farmacologia , Aminas/síntese química , Aminas/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Azidas/síntese química , Azidas/química , Sítios de Ligação/efeitos dos fármacos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Quinases Ciclina-Dependentes/química , Quinases Ciclina-Dependentes/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Ligações de Hidrogênio , Células MCF-7 , Simulação de Acoplamento Molecular , Estrutura Molecular , Pargilina/síntese química , Pargilina/química , Pargilina/farmacologia , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Células Vero
10.
Eur J Pharm Sci ; 139: 105066, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31513922

RESUMO

Thrombomodulin (TM) is an endothelial cell membrane protein that plays essential roles in controlling vascular haemostatic balance. The 4, 5, 6 EGF-like domain of TM (TM456) has cofactor activity for thrombin binding and subsequently protein C activation. Therefore, recombinant TM456 is a promising anticoagulant candidate but has a very short half-life. Ligation of poly (ethylene glycol) to a bioactive protein (PEGylation) is a practical choice to improve stability, extend circulating life, and reduce immunogenicity of the protein. Site-specific PEGylation is preferred as it could avoid the loss of protein activity resulting from nonspecific modification. We report herein two site-specific PEGylation strategies, enzymatic ligation and copper-free click chemistry (CFCC), for rTM456 modification. Recombinant TM456 with a C-terminal LPETG tag (rTM456-LPETG) was expressed in Escherichia coli for its end-point modification with NH2-diglycine-PEG5000-OMe via Sortase A-mediated ligation (SML). Similarly, an azide functionality was easily introduced at the C-terminus of rTM456-LPETG via SML with NH2-diglycine-PEG3-azide, which facilitates a site-specific PEGylation of rTM456via CFCC. Both PEGylated rTM456 conjugates retained protein C activation activity as that of rTM456. Also, they were more stable than rTM456 in Trypsin digestion assay. Further, both PEGylated rTM456 conjugates showed a concentration-dependent prolongation of thrombin clotting time (TCT) compared to non-modified protein, which confirms the effectiveness of these two site-specific PEGylation schemes.


Assuntos
Anticoagulantes/administração & dosagem , Anticoagulantes/química , Trombomodulina/administração & dosagem , Trombomodulina/química , Azidas/administração & dosagem , Azidas/química , Coagulação Sanguínea/efeitos dos fármacos , Química Click , Estabilidade de Medicamentos , Humanos , Polietilenoglicóis/administração & dosagem , Polietilenoglicóis/química , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/química , Trombina/metabolismo , Trombomodulina/genética
11.
Chem Asian J ; 14(19): 3380-3385, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31478313

RESUMO

An oligonucleotide of triazole-linked RNA (TL RNA) was synthesized by performing consecutive copper-catalyzed azide-alkyne cycloaddition reactions for elongation. The reaction conditions that had been optimized for the synthesis of 3-mer TL RNA were found to be inappropriate for longer oligonucleotides, and the conditions were reoptimized for the solid-phase synthesis of an 11-mer TL RNA oligonucleotide. Duplex formation of the 11-mer TL RNA oligonucleotide was examined with the complementary oligonucleotide of natural RNA to reveal the effects of the 2'-OH groups on the duplex stability.


Assuntos
Oligonucleotídeos/química , RNA/química , Triazóis/química , Alquinos/química , Azidas/química , Catálise , Cobre/química , Reação de Cicloadição , Simulação de Dinâmica Molecular , Conformação de Ácido Nucleico , Oligonucleotídeos/síntese química , Técnicas de Síntese em Fase Sólida
12.
Curr Microbiol ; 76(12): 1425-1434, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31552450

RESUMO

In the present study, EMA (ethidium monoazide) treatment was applied to a silty-sand reference soil prior to DNA extraction to enable a differentiation between dead and living cells. For this purpose, a reference soil was spiked with Listeria monocytogenes cells or cell equivalents, respectively. With the purpose of evaluating optimum treatment conditions, different EMA concentrations have been tested. However, the results remained largely inconclusive. Furthermore, varied dark incubation periods allowing EMA to penetrate dead cells did not allow the selective removal of DNA from membrane-compromised cells in downstream analyses. In contrast to undiluted soil, an effect of EMA treatment during DNA extraction could be observed when using a 1:10 dilution of the reference soil; however, the effect has not been sufficiently selective to act on heat-treated cells only. Although the application of EMA to soil requires further evaluation, the procedure harbors future potential for improving DNA-based approaches in microbial ecology studies.


Assuntos
Marcadores de Afinidade/química , Azidas/química , Técnicas Bacteriológicas/métodos , DNA Bacteriano/química , Listeria monocytogenes/fisiologia , Viabilidade Microbiana , Contagem de Colônia Microbiana , DNA Bacteriano/genética , DNA Bacteriano/isolamento & purificação , Listeria monocytogenes/genética , Listeria monocytogenes/isolamento & purificação , Reação em Cadeia da Polimerase , Microbiologia do Solo
13.
Molecules ; 24(18)2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31509944

RESUMO

Nucleic Acid Therapeutics (NATs), including siRNAs and AntiSense Oligonucleotides (ASOs), have great potential to drug the undruggable genome. Targeting siRNAs and ASOs to specific cell types of interest has driven dramatic improvement in efficacy and reduction in toxicity. Indeed, conjugation of tris-GalNAc to siRNAs and ASOs has shown clinical efficacy in targeting diseases driven by liver hepatocytes. However, targeting non-hepatic diseases with oligonucleotide therapeutics has remained problematic for several reasons, including targeting specific cell types and endosomal escape. Monoclonal antibody (mAb) targeting of siRNAs and ASOs has the potential to deliver these drugs to a variety of specific cell and tissue types. However, most conjugation strategies rely on random chemical conjugation through lysine or cysteine residues resulting in conjugate heterogeneity and a distribution of Drug:Antibody Ratios (DAR). To produce homogeneous DAR-2 conjugates with two siRNAs per mAb, we developed a novel two-step conjugation procedure involving microbial transglutaminase (MTGase) tagging of the antibody C-terminus with an azide-functionalized linker peptide that can be subsequently conjugated to dibenzylcyclooctyne (DBCO) bearing oligonucleotides through azide-alkyne cycloaddition. Antibody-siRNA (and ASO) conjugates (ARCs) produced using this strategy are soluble, chemically defined targeted oligonucleotide therapeutics that have the potential to greatly increase the number of targetable cell types.


Assuntos
Anticorpos/farmacologia , Imunoconjugados/química , Oligonucleotídeos Antissenso/imunologia , RNA Interferente Pequeno/imunologia , Anticorpos/química , Anticorpos/imunologia , Azidas/química , Linhagem da Célula/efeitos dos fármacos , Reação de Cicloadição , Ciclo-Octanos/química , Sistemas de Liberação de Medicamentos , Endossomos/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Hepatócitos/imunologia , Humanos , Imunoconjugados/imunologia , Imunoconjugados/farmacologia , Fígado/efeitos dos fármacos , Fígado/imunologia , Oligonucleotídeos Antissenso/antagonistas & inibidores , Oligonucleotídeos Antissenso/química , Peptídeos/química , Peptídeos/farmacologia , RNA Interferente Pequeno/antagonistas & inibidores , RNA Interferente Pequeno/química , Transglutaminases/química , Transglutaminases/imunologia , Transglutaminases/farmacologia
14.
Nat Commun ; 10(1): 4065, 2019 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-31492838

RESUMO

Unnatural monosaccharides such as azidosugars that can be metabolically incorporated into cellular glycans are currently used as a major tool for glycan imaging and glycoproteomic profiling. As a common practice to enhance membrane permeability and cellular uptake, the unnatural sugars are per-O-acetylated, which, however, can induce a long-overlooked side reaction, non-enzymatic S-glycosylation. Herein, we develop 1,3-di-esterified N-azidoacetylgalactosamine (GalNAz) as next-generation chemical reporters for metabolic glycan labeling. Both 1,3-di-O-acetylated GalNAz (1,3-Ac2GalNAz) and 1,3-di-O-propionylated GalNAz (1,3-Pr2GalNAz) exhibit high efficiency for labeling protein O-GlcNAcylation with no artificial S-glycosylation. Applying 1,3-Pr2GalNAz in mouse embryonic stem cells (mESCs), we identify ESRRB, a critical transcription factor for pluripotency, as an O-GlcNAcylated protein. We show that ESRRB O-GlcNAcylation is important for mESC self-renewal and pluripotency. Mechanistically, ESRRB is O-GlcNAcylated by O-GlcNAc transferase at serine 25, which stabilizes ESRRB, promotes its transcription activity and facilitates its interactions with two master pluripotency regulators, OCT4 and NANOG.


Assuntos
Acetilglucosamina/metabolismo , Monossacarídeos/metabolismo , Células-Tronco Embrionárias Murinas/metabolismo , Células-Tronco Pluripotentes/metabolismo , Receptores Estrogênicos/metabolismo , Animais , Azidas/química , Azidas/metabolismo , Linhagem Celular Tumoral , Autorrenovação Celular , Células Cultivadas , Glicosilação , Células HeLa , Hexosaminas/metabolismo , Humanos , Células MCF-7 , Camundongos , Monossacarídeos/química , Células-Tronco Embrionárias Murinas/citologia , Células NIH 3T3 , Células-Tronco Pluripotentes/citologia , Processamento de Proteína Pós-Traducional
15.
Soft Matter ; 15(35): 6930-6933, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31372613

RESUMO

DNA-coated inorganic particles can be prepared simply by physical adsorption of azide-functionalized diblock copolymers (polystyrene-b-poly(ethylene oxide)-azide, PS-b-PEO-N3) onto hydrophobically-modified inorganic particles, followed by strain-promoted azide-alkyne cycloaddition (SPAAC, copper-free click chemistry). This approach is applied to organosilica, silica and titania particles. The DNA-coated colloids are successfully crystallized into colloidal superstructures by a thermal annealing process using DNA-mediated assembly.


Assuntos
Alquinos/química , Azidas/química , Coloides/química , DNA/química , Polímeros/química , Dióxido de Silício/química , Titânio/química , Catálise , Química Click , Reação de Cicloadição
16.
Biosens Bioelectron ; 142: 111503, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31376716

RESUMO

Exosomes, lipid bilayer membrane vesicles, can guide various pathological and physiological processes. However, reliable, convenient and sensitive methods for exosome determination for early cancer diagnosis are still technically challenging. Herein, an electrochemical aptasensor based on click chemistry and the DNA hybridization chain reaction (HCR) for signal amplification has been developed for the ultrasensitive detection of tumor exosomes. CD63 aptamer was first immobilized on a glassy carbon electrode for capturing exosomes, and 4-oxo-2-nonenal alkyne (alkynyl-4-ONE) molecules, functionalized lipid electrophiles, were conjugated to the exosomes via the reaction of amino and aldehyde groups. Azide-labeled DNA probe as an anchor was then connected to the exosomes by copper (I)-catalyzed click chemistry. Signal amplification was achieved by HCR, and the numerous linked horseradish peroxidase (HRP) molecules could catalyze the reaction of o-phenylenediamine (OPD) and H2O2. The concentration of exosomes could be quantified by monitoring the electrochemical reduction current of 2,3-diaminophenazine (DAP). Under the optimal conditions, this method allowed the sensitive detection of exosomes in the range of 1.12 × 102 to 1.12 × 108 particles/µL with a limit of detection (LOD) of 96 particles/µL. Furthermore, the present assay enabled sensitive and accurate quantification of exosomes in human serum, and it has high potential for exosome analysis in clinical samples.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Neoplasias da Mama/patologia , Exossomos/patologia , Alquinos/química , Azidas/química , Neoplasias da Mama/sangue , Neoplasias da Mama/química , Química Click/métodos , Sondas de DNA/química , Técnicas Eletroquímicas/métodos , Exossomos/química , Feminino , Humanos , Células MCF-7 , Hibridização de Ácido Nucleico , Tetraspanina 30/análise
17.
Food Chem ; 301: 125247, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31377626

RESUMO

In this work, we developed a simple method for the preparation of N-(3-azido-2-hydroxypropyl)chitosan. We compared the antibacterial activity of N-(3-azido-2-hydroxypropyl)chitosans and previously synthesized N-(2-azidoethyl)chitosans. N-(3-azido-2-hydroxypropyl)chitosans possess higher antibacterial effect which is comparable with that of ampicillin and gentamicin. The effect is due to azido pharmacophore -CH2-CH(OH)-CH2-N3 (for N-(3-azido-2-hydroxypropyl)chitosan) or -CH2-CH2-N3 (for N-(2-azidoethyl)chitosan) introduced in chitosan chain, since the corresponding organic azides NH2-CH2-CH2-N3 and NH2-CH2-CH2-N3 are characterized by high antibacterial activity. However, high antibacterial organic azides NH2-CH2-CH2-N3 and NH2-CH2-CH2-N3 are characterized by high toxicity. Their conjugation to the chitosan chain saves their antibacterial effect, but strongly diminishes their toxicity, and the toxicity of the resulting derivatives is comparable with that of the starting chitosan. These findings are of interest to food science, since novel effective food coatings can be developed on basis of prepared derivatives.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Azidas/química , Quitosana/química , Quitosana/farmacologia , Embalagem de Alimentos , Antibacterianos/toxicidade , Quitosana/toxicidade
18.
Carbohydr Res ; 483: 107751, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31374379

RESUMO

A 6-azido-2-tosylenolate, obtained from D-glucono-1,5-lactone in six steps, underwent an intramolecular cycloaddition-elimination pathway under mild conditions, yielding a chiral, substituted 5,6-dihydro-4H-pyrrolo[1,2-c]-1,2,3-triazole. The conditions were optimized to give exclusive formation of the triazole. The mechanism appears to involve intramolecular ring closure via a 1,3-dipolar azide-alkene cycloaddition to give a 1,2,3-triazoline, followed by elimination of p-toluenesulfonic acid, leading to aromatization. Triazole products, obtained by chemical modification, are expected to display activity as enzyme inhibitors. Furthermore, partially protected derivatives of the 2-hexenoate were prepared as useful synthetic intermediates.


Assuntos
Inibidores Enzimáticos/síntese química , Pirróis/síntese química , Triazóis/síntese química , Alcenos/química , Azidas/química , Reação de Cicloadição , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Estrutura Molecular , Pirróis/química , Pirróis/farmacologia , Triazóis/química , Triazóis/farmacologia
19.
Org Biomol Chem ; 17(34): 8014-8018, 2019 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-31418442

RESUMO

The Sondheimer dialkyne is extensively used in double strain-promoted azide-alkyne cycloadditions. This reagent suffers with poor water-solubility and rapidly decomposes in aqueous solutions. This intrinsically limits its application in biological systems, and no effective solutions are currently available. Herein, we report the development of novel highly water-soluble, stable, and azide-reactive strained dialkyne reagents. To demonstrate their extensive utility, we applied our novel dialkynes to a double strain-promoted macrocyclisation strategy to generate functionalised p53-based stapled peptides for inhibiting the oncogenic p53-MDM2 interaction. These functionalised stapled peptides bind MDM2 with low nanomolar affinity and show p53 activation in a cellular environment. Overall, our highly soluble, stable and azide-reactive dialkynes offer significant advantages over the currently used Sondheimer dialkyne, and could be utilised for numerous biological applications.


Assuntos
Alquinos/química , Azidas/química , Peptídeos/farmacologia , Ligação Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Linhagem Celular , Química Click , Reação de Cicloadição , Escherichia coli , Humanos , Camundongos , Peptídeos/síntese química , Solubilidade , Triazóis/síntese química , Triazóis/farmacologia , Água/química
20.
Chem Commun (Camb) ; 55(73): 10952-10955, 2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31441915

RESUMO

Triggering antibody-mediated innate immune mechanisms to kill cancer cells is an attractive therapeutic avenue. In this context, recruitment of endogenous antibodies to the cancer cell surface could be a viable alternative to the use of monoclonal antibodies. We report on antibody-recruiting polymers containing multiple antibody-binding hapten motifs and cyclooctynes that can covalently conjugate to azides introduced onto the glycocalyx of cancer cells by metabolic labeling with azido sugars.


Assuntos
Resinas Acrílicas/química , Anticorpos/imunologia , Azidas/metabolismo , Dinitrobenzenos/imunologia , Hexosaminas/metabolismo , Resinas Acrílicas/síntese química , Animais , Azidas/química , Linhagem Celular Tumoral , Química Click , Reação de Cicloadição , Ciclo-Octanos/síntese química , Ciclo-Octanos/química , Dinitrobenzenos/síntese química , Dinitrobenzenos/química , Fluorescência , Corantes Fluorescentes/química , Glicocálix/metabolismo , Hexosaminas/química , Humanos , Camundongos , Microscopia Confocal/métodos , Microscopia de Fluorescência/métodos , Estudo de Prova de Conceito , Esferoides Celulares/metabolismo
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