RESUMEN

A method for the preparation of benzene derivatives from myo-inositol, an abundantly available phyto chemical is described. 1,3-Bridged acetals of inososes undergo step-wise elimination leading to the formation of polyoxygenated benzene derivatives. This aromatization reaction proceeds through the intermediacy of a ß-alkoxyenone, which could be isolated. This sequence of reactions starting from myo-inositol, provides a novel route for the preparation of polyoxygenated benzene derivatives including polyoxygenated biphenyl. This scheme of synthesis demonstrates the potential of myo-inositol as a sustainable non-petrochemical resource for aromatic compounds.

Asunto(s)

Benceno/química , Inositol/química , Biomasa

RESUMEN

There is a growing body of evidence suggesting that some ribonucleoside/ribonucleotide analogs may be incorporated into mitochondrial RNA by human mitochondrial DNA-dependent RNA polymerase (POLRMT) and disrupt mitochondrial RNA synthesis. An assessment of the incorporation efficiency of a ribonucleotide analog 5'-triphosphate by POLRMT may be used to evaluate the potential mitochondrial toxicity of the analog early in the development process. In this report, we provide a simple method to prepare active recombinant POLRMT. A robust in vitro nonradioactive primer extension assay was developed to assay the incorporation efficiency of ribonucleotide analog 5'-triphosphates. Our results show that many ribonucleotide analogs, including some antiviral compounds currently in various preclinical or clinical development stages, can be incorporated into newly synthesized RNA by POLRMT and that the incorporation of some of them can lead to chain termination. The discrimination (D) values of ribonucleotide analog 5'-triphosphates over those of natural ribonucleotide triphosphates (rNTPs) were measured to evaluate the incorporation efficiency of the ribonucleotide analog 5'-triphosphates by POLRMT. The discrimination values of natural rNTPs under the condition of misincorporation by POLRMT were used as a reference to evaluate the potential mitochondrial toxicity of ribonucleotide analogs. We propose the following criteria for the potential mitochondrial toxicity of ribonucleotide analogs based on D values: a safe compound has a D value of >105; a potentially toxic compound has a D value of >104 but <105; and a toxic compound has a D value of <104 This report provides a simple screening method that should assist investigators in designing ribonucleoside-based drugs having lower mitochondrial toxicity.

Asunto(s)

ARN Polimerasas Dirigidas por ADN/genética , Mitocondrias/genética , Polifosfatos/farmacología , ARN/efectos de los fármacos , Ribonucleósidos/genética , Ribonucleótidos/farmacología , Antivirales/farmacología , Humanos , Mitocondrias/efectos de los fármacos , ARN/genética

RESUMEN

Zika virus (ZIKV) is an emerging human pathogen that is spreading rapidly through the Americas and has been linked to the development of microcephaly and to a dramatically increased number of Guillain-Barré syndrome cases. Currently, no vaccine or therapeutic options for the prevention or treatment of ZIKV infections exist. In the study described in this report, we expressed, purified, and characterized full-length nonstructural protein 5 (NS5) and the NS5 polymerase domain (NS5pol) of ZIKV RNA-dependent RNA polymerase. Using purified NS5, we developed an in vitro nonradioactive primer extension assay employing a fluorescently labeled primer-template pair. Both purified NS5 and NS5pol can carry out in vitro RNA-dependent RNA synthesis in this assay. Our results show that Mn2+ is required for enzymatic activity, while Mg2+ is not. We found that ZIKV NS5 can utilize single-stranded DNA but not double-stranded DNA as a template or a primer to synthesize RNA. The assay was used to compare the efficiency of incorporation of analog 5'-triphosphates by the ZIKV polymerase and to calculate their discrimination versus that of natural ribonucleotide triphosphates (rNTPs). The 50% inhibitory concentrations for analog rNTPs were determined in an alternative nonradioactive coupled-enzyme assay. We determined that, in general, 2'-C-methyl- and 2'-C-ethynyl-substituted analog 5'-triphosphates were efficiently incorporated by the ZIKV polymerase and were also efficient chain terminators. Derivatives of these molecules may serve as potential antiviral compounds to be developed to combat ZIKV infection. This report provides the first characterization of ZIKV polymerase and demonstrates the utility of in vitro polymerase assays in the identification of potential ZIKV inhibitors.

Asunto(s)

Antivirales/farmacología , Bioensayo , ARN Polimerasa Dependiente del ARN/antagonistas & inhibidores , Ribonucleótidos/farmacología , Proteínas no Estructurales Virales/antagonistas & inhibidores , Replicación Viral/efectos de los fármacos , Virus Zika/efectos de los fármacos , Antivirales/metabolismo , Secuencia de Bases , Cationes Bivalentes , Cartilla de ADN/síntesis química , Cartilla de ADN/metabolismo , ADN de Cadena Simple/genética , ADN de Cadena Simple/metabolismo , Manganeso/metabolismo , Polifosfatos/metabolismo , Dominios Proteicos , ARN Viral/antagonistas & inhibidores , ARN Viral/biosíntesis , ARN Viral/genética , ARN Polimerasa Dependiente del ARN/genética , ARN Polimerasa Dependiente del ARN/metabolismo , Ribonucleótidos/metabolismo , Coloración y Etiquetado/métodos , Proteínas no Estructurales Virales/genética , Proteínas no Estructurales Virales/metabolismo , Virus Zika/genética , Virus Zika/metabolismo

RESUMEN

A large number of proteins in malaria parasites are anchored using glycophosphatidylinositols (GPIs) with lipid tails. These GPIs are structurally distinct from human GPIs. Plasmodium falciparum GPIs have been considered as potential vaccine candidates because these molecules are involved in inducing inflammatory responses in human hosts, and natural anti-GPI antibody responses have been shown to be associated with protection against severe disease. GPIs can also be considered as targets for rapid diagnostic tests. Because isolation of native GPIs in large quantities is challenging, development of synthetic GPI molecules can facilitate further exploration of GPI molecules for diagnostics. Here, we report synthesis and immunological characterization of a panel of malaria-specific GPI analogues. A total of three GPI analogues were chemically synthesized and conjugated to a carrier protein to immunize and generate antibodies in rabbits. The rabbit immune sera showed reactivity with synthetic GPIs and native GPIs extracted from P. falciparum parasite, as determined by Luminex and ELISA methods.

Asunto(s)

Anticuerpos Antiprotozoarios/inmunología , Glicosilfosfatidilinositoles/química , Glicosilfosfatidilinositoles/inmunología , Plasmodium falciparum/inmunología , Adyuvantes Inmunológicos/química , Animales , Anticuerpos Antiprotozoarios/química , Técnicas de Química Sintética , Proteínas Ligadas a GPI/química , Glicosilfosfatidilinositoles/síntesis química , Hemocianinas/química , Sueros Inmunes , Malaria Falciparum/diagnóstico , Conejos

RESUMEN

A panel of biotinylated bivalent H-type glycans that have been reported as binding ligands for human noroviruses were synthesized using a modular synthetic strategy. These glycoconjugates were attached to streptavidin-coated magnetic beads and used to recover human norovirus from fecal samples using a magnetic bead-based assay. The biotinylated bivalent glycans synthesized for this study exhibited similar or better capturing ability when compared to commercial biotinylated glycopolymers.

Asunto(s)

Biotinilación , Antígenos de Grupos Sanguíneos/química , Antígenos de Grupos Sanguíneos/metabolismo , Norovirus/aislamiento & purificación , Norovirus/metabolismo , Técnicas de Química Sintética , Heces/virología , Glicoconjugados/metabolismo , Humanos , Modelos Moleculares , Conformación Proteica

RESUMEN

Glycosidases are essential enzymes that cleave glycoside bonds. The presence of glycosidases have been widely used to detect pathogens, label cells/tissues, and report specific diseases. We have developed a rapid electrochemical assay to detect glycosidases. Exposure of electrochemically inactive substrates to glycosidases releases glucose, which can be measured easily using an electrochemical cell. Five different glycosidases were detected rapidly within 1 h using disposable electrodes. This assay could readily be incorporated into repurposed glucose meters to rapidly detect glycosidases, which in turn could be useful to report the presence of a pathogen or illness.

Asunto(s)

Técnicas Electroquímicas/métodos , Glicósido Hidrolasas/orina , Equipos Desechables , Técnicas Electroquímicas/instrumentación , Electrodos , Glucosa/análisis , Glucosa/metabolismo , Glicósido Hidrolasas/metabolismo , Humanos , Factores de Tiempo

RESUMEN

Synthetic sequences starting from commercially available myo-inositol necessarily involve protection-deprotection strategies of its six hydroxyl groups. Several strategies have been developed/attempted over the last several decades leading to the synthesis of naturally occurring phosphoinositols, their analogs, and cyclitol derivatives. Of late, myo-inositol 1,3-acetals, which can be obtained by the reductive cleavage of myo-inositol orthoesters have emerged as early intermediates for the synthesis of phosphorylated and other inositol derivatives. This mini-review is an attempt to illustrate the economy and convenience of using myo-inositol 1,3-acetals as early intermediates during syntheses from myo-inositol.

Asunto(s)

Acetales/química , Inositol/análogos & derivados , Acetales/síntesis química , Inositol/síntesis química , Inositol/química , Conformación Molecular

RESUMEN

Concise and efficient syntheses of the aminocyclitol cores of hygromycin A (HMA) and methoxyhygromycin (MHM) have been achieved starting from readily available myo-inositol. Reductive cleavage of myo-inositol orthoformate to the corresponding 1,3-acetal, stereospecific introduction of the amino group via the azide, and resolution of a racemic cyclitol derivative as its diastereomeric mandelate esters are the key steps in the synthesis. Synthesis of the aminocyclitol core of hygromycin A involved chromatography in half of the total number of steps, and the aminocyclitol core of methoxyhygromycin involved only one chromatography.

Asunto(s)

Cinamatos/síntesis química , Ciclitoles/química , Higromicina B/análogos & derivados , Inositol/química , Conformación de Carbohidratos , Cinamatos/química , Higromicina B/síntesis química , Higromicina B/química , Inositol/análogos & derivados , Estereoisomerismo

RESUMEN

The title achiral compound, C(35)H(34)O(7), crystallizes in the chiral monoclinic space group P2(1). The molecules are densely packed to form a helical assembly along the crystallographic twofold screw axis via C-H···O and C-H···π interactions. Interestingly, the unit-translated helical chains are loosely connected via a rather uncommon edge-to-edge Ph-H···H-Ph short contact (H···H = 2.33 Å).

RESUMEN

Xanthates of 1,3-benzylidene acetal derivatives of myo- and neo-inositols undergo dideoxygenation under Barton-McCombie conditions, as a result of intramolecular abstraction of the benzylidene acetal hydrogen and subsequent cleavage of the acetal ring. Scrutiny of structure of these bicyclic inositol derivatives shows that although the conformation of the two rings can vary depending on the configuration of the inositol ring and the phase in which the molecules are present, both the xanthates lead to the formation of the same dideoxyinositol. DFT calculations on these molecular systems suggest that neo-inositol derivatives undergo conformational change prior to radical formation while myo-inositol derivatives undergo conformational change subsequent to radical formation, during the deoxygenation reaction. A low barrier for intramolecular hydrogen transfer supports the extreme facility of this deoxygenation reaction.

Asunto(s)

Acetales/química , Compuestos de Bencilideno/química , Inositol/química , Conformación Molecular , Oxígeno/química , Teoría Cuántica , Radicales Libres/química , Modelos Moleculares