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1.
Nature ; 585(7826): 530-537, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32968259

RESUMO

Post-translational modifications (PTMs) greatly expand the structures and functions of proteins in nature1,2. Although synthetic protein functionalization strategies allow mimicry of PTMs3,4, as well as formation of unnatural protein variants with diverse potential functions, including drug carrying5, tracking, imaging6 and partner crosslinking7, the range of functional groups that can be introduced remains limited. Here we describe the visible-light-driven installation of side chains at dehydroalanine residues in proteins through the formation of carbon-centred radicals that allow C-C bond formation in water. Control of the reaction redox allows site-selective modification with good conversions and reduced protein damage. In situ generation of boronic acid catechol ester derivatives generates RH2C• radicals that form the native (ß-CH2-γ-CH2) linkage of natural residues and PTMs, whereas in situ potentiation of pyridylsulfonyl derivatives by Fe(II) generates RF2C• radicals that form equivalent ß-CH2-γ-CF2 linkages bearing difluoromethylene labels. These reactions are chemically tolerant and incorporate a wide range of functionalities (more than 50 unique residues/side chains) into diverse protein scaffolds and sites. Initiation can be applied chemoselectively in the presence of sensitive groups in the radical precursors, enabling installation of previously incompatible side chains. The resulting protein function and reactivity are used to install radical precursors for homolytic on-protein radical generation; to study enzyme function with natural, unnatural and CF2-labelled post-translationally modified protein substrates via simultaneous sensing of both chemo- and stereoselectivity; and to create generalized 'alkylator proteins' with a spectrum of heterolytic covalent-bond-forming activity (that is, reacting diversely with small molecules at one extreme or selectively with protein targets through good mimicry at the other). Post-translational access to such reactions and chemical groups on proteins could be useful in both revealing and creating protein function.


Assuntos
Luz , Processamento de Proteína Pós-Traducional/efeitos da radiação , Proteínas/química , Proteínas/metabolismo , Alanina/análogos & derivados , Alanina/química , Alanina/metabolismo , Sítios de Ligação , Carbono/química , Carbono/metabolismo , Enzimas/química , Enzimas/metabolismo , Ésteres/síntese química , Ésteres/química , Células HeLa , Humanos , Hidrocarbonetos Fluorados/química , Hidrocarbonetos Fluorados/metabolismo , Indicadores e Reagentes/química , Oxirredução , Processos Fotoquímicos/efeitos da radiação , Domínios e Motivos de Interação entre Proteínas
2.
Nat Commun ; 11(1): 4170, 2020 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-32820174

RESUMO

Sulfur-sulfur motifs widely occur in vital function and drug design, which yearns for polysulfide construction in an efficient manner. However, it is a great challenge to install desired functional groups on both sides of sulfur-sulfur bonds at liberty. Herein, we designed a mesocyclic bilateral disulfurating reagent for sequential assembly and modular installation of polysulfides. Based on S-O bond dissociation energy imparity (mesocyclic compared to linear imparity is at least 5.34 kcal mol-1 higher), diverse types of functional molecules can be bridged via sulfur-sulfur bonds distinctly. With these stable reagents, excellent reactivities with nucleophiles including C, N and S are comprehensively demonstrated, sequentially installing on both sides of sulfur-sulfur motif with various substituents to afford six species of unsymmetrical polysulfides including di-, tri- and even tetra-sulfides. Life-related molecules, natural products and pharmaceuticals can be successively cross-linked with sulfur-sulfur bond. Remarkably, the cyclization of tri- and tetra-peptides affords 15- and 18-membered cyclic disulfide peptides with this reagent, respectively.


Assuntos
Dissulfetos/química , Indicadores e Reagentes/química , Peptídeos/química , Sulfetos/química , Enxofre/química , Produtos Biológicos/química , Técnicas de Química Sintética/métodos , Ciclização , Indicadores e Reagentes/síntese química , Modelos Químicos , Estrutura Molecular , Oxirredução , Preparações Farmacêuticas/química
3.
Nat Commun ; 11(1): 2756, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32488003

RESUMO

Trifluoroethanol and difluoroethanol units are important motifs in bioactive molecules, but the methods to direct incorporate these units are limited. Herein, we report two organosilicon reagents for the transfer of trifluoroethanol and difluoroethanol units into molecules. Through intramolecular C-Si bond activation by alkoxyl radicals, these reagents were applied in allylation, alkylation and alkenylation reactions, enabling efficient synthesis of various tri(di)fluoromethyl group substituted alcohols. The broad applicability and general utility of the approach are highlighted by late-stage introduction of these fluoroalkyl groups to complex molecules, and the synthesis of antitumor agent Z and its difluoromethyl analog Z'.


Assuntos
Etanol/análogos & derivados , Etanol/química , Compostos de Organossilício/química , Trifluoretanol/química , Álcoois/química , Alquilação , Técnicas de Química Sintética , Indicadores e Reagentes/química , Estrutura Molecular
4.
J Vet Diagn Invest ; 32(4): 577-580, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32450762

RESUMO

Rift Valley fever virus (RVFV) causes Rift Valley fever (RVF), resulting in morbidity and mortality in humans and ruminants. Evidence of transboundary outbreaks means that RVFV remains a threat to human health and livestock industries in countries that are free from the disease. To enhance surveillance capability, methods for detection of RVFV are required. The generation of reagents suitable for the detection of RVFV antigen in formalin-fixed, paraffin-embedded tissues from infected animals have been developed and are described herein. Recombinant nucleoprotein (rNP) was expressed in Escherichia coli and purified using immobilized metal ion affinity chromatography. Purified rNP was used as an immunogen to produce anti-NP polyclonal antisera in rabbits for use in detection of RVFV NP in experimentally infected animals by immunohistochemistry. Antisera raised in rabbits against rNP were able to recognize viral NP antigen in fixed infected Vero cell pellets and sheep liver. Therefore, the methods and reagents described herein are useful in assays for detection of RVFV infections in animals, for research and surveillance purposes.


Assuntos
Febre do Vale de Rift/diagnóstico , Vírus da Febre do Vale do Rift/isolamento & purificação , Doenças dos Ovinos/diagnóstico , Animais , Indicadores e Reagentes/química , Ovinos
5.
Forensic Sci Int ; 310: 110259, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32224429

RESUMO

At the start of this study, no reliable, consistent, challenging and representative positive control test was commercially available for fingermark visualisation techniques. The goal of this study was to determine the lower limits of detection (LOD) of the fingermark visualisation techniques ninhydrin and 1,2-indanedione-ZnCl and developing positive control tests for these techniques. Spot tests with an amino acid solution were produced to determine the lower LOD's. Secondly, a Dimatix Materials Printer (DMP) was used to print simulated fingermarks using different concentrations of an amino acid solution, to determine the lower LOD of ninhydrin and 1,2-indanedione-ZnCl using the DMP. Concept positive control tests were developed using the lower LOD of ninhydrin and 1,2-indanedione-ZnCl. These were later on adjusted, to form the definitive positive control tests, after a testing period of two months.


Assuntos
Dermatoglifia , Indanos/química , Indicadores e Reagentes/química , Ninidrina/química , Patologia Legal , Humanos
6.
Chemistry ; 26(43): 9430-9444, 2020 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-32227537

RESUMO

The last decade has witnessed the rapid development of high-valent Pd-involved organic transformations. This has also led to a steadily growing number of publications concerning the preparation of isolable and characterizable palladium(III) and palladium(IV) complexes. A variety of one-electron and two-electron oxidants have been employed to give access to high-oxidation-state Pd compounds. Undoubtedly, the study of these stoichiometric reactions has great implications for relevant Pd-mediated catalysis. In this minireview, the focus is on the synthetic approaches to structurally determined PdIII/IV complexes starting from their PdII precursors, and the advances in this research area from early 2010 to late 2019 will be highlighted. Chemical oxidations exploiting various oxidizing agents including 1) hypervalent iodine reagents; 2) halogens; 3) electrophilic fluorination reagents; 4) alkyl/aryl halides; 5) ferrocenium salts; 6) peroxides/O2 ; 7) sulfonyl chlorides; and 8) others are covered. A "greener" electrooxidation manner has also been reviewed.


Assuntos
Compostos Ferrosos/química , Paládio/química , Catálise , Elétrons , Halogenação , Halogênios/química , Indicadores e Reagentes/química , Iodo/química , Oxirredução
7.
Science ; 367(6482): 1151-1156, 2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-32139547

RESUMO

The regulation of messenger RNA levels in mammalian cells can be achieved by the modulation of synthesis and degradation rates. Metabolic RNA-labeling experiments in bulk have quantified these rates using relatively homogeneous cell populations. However, to determine these rates during complex dynamical processes, for instance during cellular differentiation, single-cell resolution is required. Therefore, we developed a method that simultaneously quantifies metabolically labeled and preexisting unlabeled transcripts in thousands of individual cells. We determined synthesis and degradation rates during the cell cycle and during differentiation of intestinal stem cells, revealing major regulatory strategies. These strategies have distinct consequences for controlling the dynamic range and precision of gene expression. These findings advance our understanding of how individual cells in heterogeneous populations shape their gene expression dynamics.


Assuntos
Estabilidade de RNA , RNA Mensageiro/metabolismo , Análise de Sequência de RNA/métodos , Análise de Célula Única/métodos , Transcrição Genética , Animais , Humanos , Indicadores e Reagentes/química , Células K562 , Camundongos , Uridina/análogos & derivados
8.
Nature ; 579(7799): 379-384, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32188949

RESUMO

Automated synthesis platforms accelerate and simplify the preparation of molecules by removing the physical barriers to organic synthesis. This provides unrestricted access to biopolymers and small molecules via reproducible and directly comparable chemical processes. Current automated multistep syntheses rely on either iterative1-4 or linear processes5-9, and require compromises in terms of versatility and the use of equipment. Here we report an approach towards the automated synthesis of small molecules, based on a series of continuous flow modules that are radially arranged around a central switching station. Using this approach, concise volumes can be exposed to any reaction conditions required for a desired transformation. Sequential, non-simultaneous reactions can be combined to perform multistep processes, enabling the use of variable flow rates, reuse of reactors under different conditions, and the storage of intermediates. This fully automated instrument is capable of both linear and convergent syntheses and does not require manual reconfiguration between different processes. The capabilities of this approach are demonstrated by performing optimizations and multistep syntheses of targets, varying concentrations via inline dilutions, exploring several strategies for the multistep synthesis of the anticonvulsant drug rufinamide10, synthesizing eighteen compounds of two derivative libraries that are prepared using different reaction pathways and chemistries, and using the same reagents to perform metallaphotoredox carbon-nitrogen cross-couplings11 in a photochemical module-all without instrument reconfiguration.


Assuntos
Técnicas de Química Sintética/instrumentação , Técnicas de Química Sintética/métodos , Triazóis/síntese química , Anticonvulsivantes/síntese química , Anticonvulsivantes/química , Automação/instrumentação , Automação/métodos , Carbono/química , Indicadores e Reagentes/química , Nitrogênio/química , Oxirredução , Processos Fotoquímicos , Bibliotecas de Moléculas Pequenas/síntese química , Bibliotecas de Moléculas Pequenas/química , Software , Soluções/química , Triazóis/química
9.
PLoS One ; 15(3): e0226467, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32203515

RESUMO

The aim of this study was to compare the Candida bromcresol green (BCG) medium with the chromogenic (CHROM) Brilliance Candida agar and Sabouraud dextrose agar (SDA) media in regard to their capability of detecting Candida isolates from mono- or dual-species cultures. We prepared Candida isolates' suspensions to obtain mono-species (n = 18) or dual-species (n = 153) culture plates per each medium, and three readers independently observed 513 plates at 24-h, 48-h and 72-h incubation time. We scored reading results as correct, over or under detection compared to the expected species number(s). BCG showed significantly higher correct-detection and lower under-detection rates for all Candida species when observed by at least one reader. At 24-h reading, 12 mono-species cultures had correct (or over) detections in all media, whereas 106, 60 and 78 dual-species cultures had correct (or over) detections in BCG, CHROM or SDA, respectively. BCG provides the basis for an accurate laboratory diagnosis of Candida infections.


Assuntos
Ágar/química , Candida/isolamento & purificação , Candidíase/diagnóstico , Meios de Cultura/química , Indicadores e Reagentes/química , Candidíase/microbiologia , Humanos , Técnicas Microbiológicas/métodos
10.
Haemophilia ; 26(2): 340-345, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32006459

RESUMO

INTRODUCTION: Higher potency is obtained with chromogenic substrate (CS) methods and one-stage (OS) method with SynthAFax vs silica-based OS methods on analysis of albutrepenonacog alpha (rFIX fused with albumin, rFIX-FP). AIM: Investigation of the effect of contact activator in search for explanation of discrepancy between methods. METHODS: Chromogenic Rox Factor IX method and OS methods with Pathromtin SL, SynthAFax or new OS method variants using different phospholipid emulsions and addition of either colloidal silica to create APTT reagents or addition of human FXIa together with calcium ions, in the latter case omitting contact activation. The effect of (a) adding different amounts of colloidal silica or (b) mixtures of Pathromtin SL and purified phospholipids immediately before addition of FXIa and calcium chloride was also explored. FIX activation via tissue factor/FVIIa was also made. RESULTS: FIX potency of rFIX-FP when using APTT reagents with pure phospholipid emulsions with added colloidal silica was similar to OS method with Pathromtin SL. In contrast, close to 80% higher FIX potency for rFIX-FP, and similar to OS method with SynthAFax and to the CS method, was obtained when FXIa replaced contact activation. No discrepancies were obtained for plasma-derived FIX. Gradual decrease of colloidal silica or decreasing proportion of Pathromtin SL added just before addition of FXIa raised rFIX-FP potency to that obtained with SynthAFax and Rox Factor IX. Supportive results were obtained with the tissue factor/FVIIa method. CONCLUSION: Colloidal silica and Pathromtin SL impair activation of rFIX-FP, causing underestimation of rFIX-FP potency.


Assuntos
Testes de Coagulação Sanguínea/métodos , Indicadores e Reagentes/química , Tempo de Tromboplastina Parcial/métodos , Humanos
11.
Molecules ; 25(3)2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-32013217

RESUMO

A straightforward method for the preparation of trisphosphinite ligands in one step, using only commercially available reagents (1,1,1-tris(4-hydroxyphenyl)ethane and chlorophosphines) is described. We have made use of this approach to prepare a small family of four trisphosphinite ligands of formula [CH3C{(C6H4OR2)3], where R stands for Ph (1a), Xyl (1b, Xyl = 2,6-Me2-C6H3), iPr (1c), and Cy (1d). These polyfunctional phosphinites allowed us to investigate their coordination chemistry towards a range of late transition metal precursors. As such, we report here the isolation and full characterization of a number of Au(I), Ag(I), Cu(I), Ir(III), Rh(III) and Ru(II) homotrimetallic complexes, including the structural characterization by X-ray diffraction studies of six of these compounds. We have observed that the flexibility of these trisphosphinites enables a variety of conformations for the different trimetallic species.


Assuntos
Compostos Organometálicos/química , Indicadores e Reagentes/química , Ligantes , Modelos Moleculares , Fosfinas/química , Difração de Raios X
12.
Molecules ; 25(3)2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32046047

RESUMO

Various substituted bis-(aryl)manganese species were prepared from aryl bromides by one-pot insertion of magnesium turnings in the presence of LiCl and in situ trans-metalation with MnCl2 in THF at -5 °C within 2 h. These bis-(aryl)manganese reagents undergo smooth iron-catalyzed cross-couplings using 10 mol% Fe(acac)3 with various functionalized alkenyl iodides and bromides in 1 h at 25 °C. The aryl-alkenyl cross-coupling reaction mechanism was thoroughly investigated through paramagnetic 1H-NMR, which identified the key role of tris-coordinated ate-iron(II) species in the catalytic process.


Assuntos
Ferro/química , Manganês/química , Catálise , Indicadores e Reagentes/química , Magnésio/química , Compostos Organometálicos/química , Espectroscopia de Prótons por Ressonância Magnética/métodos
13.
Diagn Microbiol Infect Dis ; 96(4): 114926, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32044188

RESUMO

Routine identification of carbapenemase-producing bacterial isolates is a lengthy process often taking up to 72 h to generate results with standard culture-based tests. Here we describe a rapid test based on the hydrolysis of nitrocefin to identify isolates producing ß-lactamase enzymes. A cocktail of inhibitors has been optimized in the reaction mix to provide specificity for carbapenemase enzymes. The developed assay has also been translated to a microfluidic platform with an optical readout (optofluidic chip). The chip has a long absorbance path (25 mm) to provide high sensitivity. A sample-to-answer has been achieved in under 30 min on these chips using colonies from culture plates. The test on this platform has the potential to provide a rapid indicative (presumptive positive) test for carbapenemase producers direct from bacteria isolated from patient samples, to rapidly trigger infection control measures and identify samples that should be prioritized for more specialized carbapenemase diagnostic assays.


Assuntos
Proteínas de Bactérias/análise , Cefalosporinas/farmacologia , Enterobacteriaceae/efeitos dos fármacos , Microfluídica/métodos , beta-Lactamases/análise , Técnicas Bacteriológicas , Colorimetria/instrumentação , Enterobacteriaceae/enzimologia , Hidrólise , Indicadores e Reagentes/química , Dispositivos Lab-On-A-Chip , Testes de Sensibilidade Microbiana , Miniaturização/instrumentação , Fenótipo , Pseudomonas/efeitos dos fármacos , Pseudomonas/enzimologia , Sensibilidade e Especificidade
14.
Anal Bioanal Chem ; 412(8): 1741-1755, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32043203

RESUMO

Previously, we demonstrated capture and concentration of Salmonella enterica subspecies enterica ser. Typhimurium using magnetic ionic liquids (MILs), followed by rapid isothermal detection of captured cells via recombinase polymerase amplification (RPA). Here, we report work intended to explore the broader potential of MILs as novel pre-analytical capture reagents in food safety and related applications. Specifically, we evaluated the capacity of the ([P66614+][Ni(hfacac)3-]) ("Ni(II)") MIL to bind a wider range of human pathogens using a panel of Salmonella and Escherichia coli O157:H7 isolates, including a "deep rough" strain of S. Minnesota. We extended this exploration further to include other members of the family Enterobacteriaceae of food safety and clinical or agricultural significance. Both the Ni(II) MIL and the ([P66614+][Dy(hfacac)4-]) ("Dy(III)") MIL were evaluated for their effects on cell viability and structure-function relationships behind observed antimicrobial activities of the Dy(III) MIL were determined. Next, we used flow imaging microscopy (FIM) of Ni(II) MIL dispersions made in model liquid media to examine the impact of increasing ionic complexity on MIL droplet properties as a first step towards understanding the impact of suspension medium properties on MIL dispersion behavior. Finally, we used FIM to examine interactions between the Ni(II) MIL and Serratia marcescens, providing insights into how the MIL may act to capture and concentrate Gram-negative bacteria in aqueous samples, including food suspensions. Together, our results provide further characterization of bacteria-MIL interactions and support the broader utility of the Ni(II) MIL as a cell-friendly capture reagent for sample preparation prior to cultural or molecular analyses. Graphical abstract.


Assuntos
Enterobacteriaceae/metabolismo , Líquidos Iônicos/metabolismo , Magnetismo , Enterobacteriaceae/classificação , Enterobacteriaceae/isolamento & purificação , Indicadores e Reagentes/química , Especificidade da Espécie , Água
15.
Chem Commun (Camb) ; 56(19): 2897-2900, 2020 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-32037418

RESUMO

[Tm(DPA)3]3- was used to generate multiple, paramagnetic nuclear Overhauser effect NMR spectra of cationic peptides when weakly bound to a lipopolysaccharide micelle. Increased spectral resolution combined with a marked increase in the number of distance restraints yielded high resolution structures of polymyxin and MSI-594 in the liposaccharide bound state.


Assuntos
Peptídeos Catiônicos Antimicrobianos/química , Elementos da Série dos Lantanídeos/química , Micelas , Ressonância Magnética Nuclear Biomolecular/métodos , Indicadores e Reagentes/química , Peptídeos/química , Polimixina B/química , Conformação Proteica
16.
Chem Commun (Camb) ; 56(19): 2917-2920, 2020 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-32037436

RESUMO

Combinatorial cyclization of hundreds to thousands of random linear peptides by structurally diverse chemical linkers offers access to large macrocyclic compound libraries. A bottleneck in the development of such libraries is the preparation of large numbers of short random linear peptides. Herein, we present a tag-based strategy that is not dependent on a throughput-limiting chromatographic purification step and thus enables parallel production of short peptides. In brief, peptides are synthesized on solid phase as conjugates with a disulfide-linked Cys-Gly-Arg-Trp tetra-peptide tag. The charged arginine residue in the tag allows for purification of the peptides by diethyl ether-precipitation and the tryptophan allows for quantification of the product by absorption measurement. Addition of a reducing agent releases the short peptides from the tag. The released sulfhydryl group in the peptide can readily be used for cyclization of the peptide library with bis-electrophilic linker reagents.


Assuntos
Dissulfetos/química , Oligopeptídeos/química , Cromatografia Líquida , Indicadores e Reagentes/química , Espectrometria de Massas , Oligopeptídeos/síntese química , Oligopeptídeos/isolamento & purificação , Biblioteca de Peptídeos
17.
Nat Commun ; 11(1): 1015, 2020 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-32081914

RESUMO

Many reagents have been developed for cysteine-specific protein modification. However, few of them allow for multi-functionalization of a single Cys residue and disulfide bridging bioconjugation. Herein, we report 3-bromo-5-methylene pyrrolones (3Br-5MPs) as a simple, robust, and versatile class of reagents for cysteine-specific protein modification. These compounds can be facilely synthesized via a one-pot mild reaction and they show comparable tagging efficiency but higher cysteine specificity than the maleimide counterparts. The addition of cysteine to 3Br-5MPs generates conjugates that are amenable to secondary addition by another thiol or cysteine, making 3Br-5MPs valuable for multi-functionalization of a single cysteine and disulfide bridging bioconjugation. The labeling reaction and subsequent treatments are mild enough to produce stable and active protein conjugates for biological applications.


Assuntos
Cisteína/química , Proteínas/química , Técnicas de Química Sintética/métodos , Dissulfetos/química , Indicadores e Reagentes/química , Fenômenos de Química Orgânica , Pirróis/química , Somatostatina/química
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 230: 118042, 2020 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-31972466

RESUMO

In the present study, the binding interactions of chloroxine, an antibacterial drug and antibiotic agent with calf thymus-deoxyribonucleic acid (ct-DNA) and human serum albumin (HSA) have been deliberated under simulative physiological conditions (pH = 7.40) employing multiple biophysical, atomic force microscopy and molecular modeling approaches. The ct-DNA binding properties of chloroxine exhibit that it binds to ct-DNA through a groove binding mode, and the binding constant values were computed employing the absorption and emission spectral data. The fluorescence study shows the presence of the static quenching mechanism in the ct-DNA- chloroxine interaction. These results are further supported by UV-vis spectra. Large complexes contain the ct-DNA chains with an average size of 225.45 nm were observed by employing AFM for chloroxine -ct-DNA. The results revealed that the fluorescence quenching of albumin by chloroxine was a static quenching process as a result of albumin-chloroxine (1:1) complex. The distance between chloroxine and albumin was obtained based on the Förster's theory of non-radiative energy transfer. The results of AFM, synchronous and three-dimensional fluorescence spectra all revealed that chloroxine induced the conformational changes of albumin. Molecular docking technology represents the binding of chloroxine to the major groove of ct-DNA and site I (subdomain II A) of albumin.


Assuntos
Antibacterianos/metabolismo , Cloroquinolinóis/metabolismo , DNA/metabolismo , Indicadores e Reagentes/metabolismo , Microscopia de Força Atômica/métodos , Albumina Sérica Humana/metabolismo , Espectrometria de Fluorescência/métodos , Antibacterianos/química , Sítios de Ligação , Cloroquinolinóis/química , DNA/química , Transferência de Energia , Humanos , Indicadores e Reagentes/química , Modelos Moleculares , Simulação de Acoplamento Molecular , Ligação Proteica , Albumina Sérica Humana/química , Termodinâmica
19.
Org Biomol Chem ; 18(4): 767-770, 2020 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-31912847

RESUMO

Phosphocholine is a small haptenic molecule that is both a precursor and degradation product of choline. Phosphocholine decorates a number of biologics such as lipids and oligosaccharides. In this study, an air and bench stable phosphocholine donor has been developed and evaluated with a number of alcohol acceptors. Using a one-pot, three-step sequence, (phosphitylation, oxidation, and phosphate deprotection) phosphocholine derivatives are synthesized in high yields. Of particular interest is the synthesis of miltefosine, the lone oral drug approved to treat leishmaniasis. Due to its prohibitive expense ($1500 per g), miltefosine is not accesable for the majority of the world's patients. Based on the described reaction sequence, this drug can be produced for $25 per g.


Assuntos
Álcoois/química , Indicadores e Reagentes/química , Fosforilcolina/análogos & derivados , Antiprotozoários/síntese química , Indicadores e Reagentes/síntese química , Modelos Químicos , Oxirredução , Fosforilcolina/síntese química
20.
J Chromatogr A ; 1618: 460869, 2020 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-31959456

RESUMO

Prostaglandins (PGs) are vitally important unsaturated fatty acids involved in arachidonic acid (AA) metabolism, participating in numerous pathophysiological processes, especially in maintaining the homeostasis of uterus. Therefore, quantitative analysis of PGs is of great importance for uncovering potential mechanisms of PGs related diseases. However, methods for determining PGs in uterine samples have not been reported. In this study, an ultra high-performance liquid chromatography/mass spectrometry (UHPLC-MS/MS) method was established to quantify PGs in uterine samples, using N,N-Dimethylethylenediamine (DMED) and N,N-Diethylethylenediamine (DEED) as derivatization reagents. The derivatization could be finished at 37 °C for 30 min catalyzed by 1-N,N,N',N'-Tetramethyl-O-(7-azabenzotriazol-1-yl) uronium hexafluorophosphate (HATU). This is a mild condition suitable for most of biological samples. The DMED labeling of PGs could significantly enhance their response compared to those of underived ones. This method exhibited excellent linearity (R2 > 0.997) and precision for the determination of PGs in uterine samples (CV ≤ 12.9%). The extraction recoveries of PGs were ranged from 83.0 to 100% and matrix effects were ranged from 86.3 to 106%, indicating DEED labeled standards could be used as internal standards for PGs quantification. With the proposed method, we successfully quantified PGs in rat uterus. The results showed their levels were significant changed in abnormal uterine bleeding (AUB) rats, suggesting that PGs might be involved in the pathological process of AUB. This established analogous reagents derivatization based UHPLC-MS/MS method could be used as a powerful tool to monitor PGs, providing insights to the precise mechanism of PG action on the endometrium.


Assuntos
Técnicas de Química Analítica/métodos , Cromatografia Líquida de Alta Pressão , Prostaglandinas/análise , Espectrometria de Massas em Tandem , Útero/química , Animais , Feminino , Indicadores e Reagentes/química , Ratos , Doenças Uterinas/fisiopatologia , Útero/fisiopatologia
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