Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros

Base de dados
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Nature ; 603(7901): 439-444, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35296845

RESUMO

The introduction of molecular complexity in an atom- and step-efficient manner remains an outstanding goal in modern synthetic chemistry. Artificial biosynthetic pathways are uniquely able to address this challenge by using enzymes to carry out multiple synthetic steps simultaneously or in a one-pot sequence1-3. Conducting biosynthesis ex vivo further broadens its applicability by avoiding cross-talk with cellular metabolism and enabling the redesign of key biosynthetic pathways through the use of non-natural cofactors and synthetic reagents4,5. Here we describe the discovery and construction of an enzymatic cascade to MK-1454, a highly potent stimulator of interferon genes (STING) activator under study as an immuno-oncology therapeutic6,7 (ClinicalTrials.gov study NCT04220866 ). From two non-natural nucleotide monothiophosphates, MK-1454 is assembled diastereoselectively in a one-pot cascade, in which two thiotriphosphate nucleotides are simultaneously generated biocatalytically, followed by coupling and cyclization catalysed by an engineered animal cyclic guanosine-adenosine synthase (cGAS). For the thiotriphosphate synthesis, three kinase enzymes were engineered to develop a non-natural cofactor recycling system in which one thiotriphosphate serves as a cofactor in its own synthesis. This study demonstrates the substantial capacity that currently exists to use biosynthetic approaches to discover and manufacture complex, non-natural molecules.


Assuntos
Guanosina , Nucleotidiltransferases , Adenosina , Animais , Interferons , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Nucleotidiltransferases/metabolismo , Transdução de Sinais
2.
J Am Chem Soc ; 131(35): 12524-5, 2009 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-19678702

RESUMO

Access to novel forms of (+)-saxitoxin (STX), a potent and selective inhibitor of voltage-gated Na(+) ion channels, has been made possible through de novo synthesis. Saxitoxin is believed to lodge in the outer mouth of the channel pore, thereby stoppering ion flux. Herein, we demonstrate that modification of the C13-carbamoyl unit can be accommodated in the binding site of the protein without significantly reducing ligand-receptor affinity. These discoveries have emboldened efforts to prepare photoaffinity-labeled and other unique forms of STX as pharmacological tools for interrogating both the molecular architecture and function of Na(+) channels. A synthetic plan that makes such compounds generally available is described.


Assuntos
Saxitoxina/síntese química , Bloqueadores dos Canais de Sódio/síntese química , Canais de Sódio/metabolismo , Animais , Células CHO , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Condutividade Elétrica , Modelos Moleculares , Porosidade , Conformação Proteica , Ratos , Saxitoxina/farmacologia , Bloqueadores dos Canais de Sódio/farmacologia , Canais de Sódio/química
3.
Org Lett ; 6(11): 1857-60, 2004 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-15151432

RESUMO

Lewis-base-catalyzed cycloisomerization of bis(enones) to decalins has been demonstrated as an alternative to the traditional Lewis acid catalyzed Diels-Alder cycloaddition. In this process, a trialkylphosphine mediates both bond formation steps in two distinct catalytic cycles. The single-pot operation generates two carbon-carbon bonds and up to five contiguous stereocenters in one step, starting from achiral, aliphatic substrates; eight examples are provided. [reaction: see text]

4.
Chem Biol ; 19(7): 902-12, 2012 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-22840778

RESUMO

A desire to better understand the role of voltage-gated sodium channels (Na(V)s) in signal conduction and their dysregulation in specific disease states motivates the development of high precision tools for their study. Nature has evolved a collection of small molecule agents, including the shellfish poison (+)-saxitoxin, that bind to the extracellular pore of select Na(V) isoforms. As described in this report, de novo chemical synthesis has enabled the preparation of fluorescently labeled derivatives of (+)-saxitoxin, STX-Cy5, and STX-DCDHF, which display reversible binding to Na(V)s in live cells. Electrophysiology and confocal fluorescence microscopy studies confirm that these STX-based dyes function as potent and selective Na(V) labels. The utility of these probes is underscored in single-molecule and super-resolution imaging experiments, which reveal Na(V) distributions well beyond the optical diffraction limit in subcellular features such as neuritic spines and filopodia.


Assuntos
Fluorescência , Corantes Fluorescentes/farmacologia , Saxitoxina/farmacologia , Canais de Sódio/metabolismo , Animais , Relação Dose-Resposta a Droga , Eletrofisiologia , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/química , Microscopia Confocal , Modelos Moleculares , Estrutura Molecular , Células PC12 , Ratos , Saxitoxina/análogos & derivados , Saxitoxina/química , Canais de Sódio/química , Relação Estrutura-Atividade
5.
J Org Chem ; 67(14): 4833-8, 2002 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-12098295

RESUMO

5,5-Dimethyl-1,4,2-dioxazoles are readily installed by transketalization of 2,2-diethoxypropane, where both the NH and OH moieties are protected in a nonprotic form. The dioxazoles are stable to a wide variety of reaction conditions and readily revert back to the hydroxamic acid by treatment with Nafion-H in 2-propanol. The method is applicable to primary, secondary, tertiary, and aromatic hydroxamic acids, and the acidity of the protons adjacent to the dioxazole allows alpha-functionalization.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA