Molecular Programming Design of Glyconucleic Acid Aptamer with High Stability.

Functional nucleic acids (FNAs), possessing specific biological functions beyond their informational roles, have gained widespread attention in disease therapeutics. However, their clinical application is severely limited by their low serum stability in complex physiological environments. In this work, a precise molecular programming strategy is explored to prepare glyconucleic acid aptamers (GNAAs) with high serum stability.

Oligonucleotide Containing 8-Trifluoromethyl-2'-Deoxyguanosine as a Z-DNA Probe.

Z-DNA structure is a noncanonical left-handed alternative form of DNA, which has been suggested to be biologically important and is related to several genetic diseases and cancer. Therefore, investigation of Z-DNA structure associated with biological events is of great importance to understanding the functions of these molecules. Here, we described the development of a trifluoromethyl labeled deoxyguanosine derivative and employed it as a F NMR probe to study Z-form DNA structure in vitro and in living cells.

Observation of Z-DNA Structure via the Synthesis of Oligonucleotide DNA Containing 8-Trifluoromethyl-2-Deoxyguanosine.

This article contains detailed synthetic protocols for the preparation of DNA oligonucleotides containing 8-trifluoromethyl-2'-deoxyguanosine ( dG) and their application to observe Z-DNA structure in vitro and in living HeLa cells. First, using a catalytic system consisting of FeSO , H SO , and H O in DMSO, we achieved a one-step synthesis of dG through a radical reaction between deoxyguanosine (dG) and CF I, with a yield of 45%. We then obtained the 3'-phosphoramidite of dG through a routine three-step procedure.

Improving Thermodynamic Stability and Anticoagulant Activity of a Thrombin Binding Aptamer by Incorporation of 8-trifluoromethyl-2'-deoxyguanosine.

In this study, we incorporated 8-trifluoromethyl-2'-deoxyguanosine (G) into a thrombin binding aptamer (TBA). Circular dichroism, nuclear magnetic resonance (NMR), electrophoresis, and prothrombin time (PT) assay were performed to investigate the structure, thermodynamic stability, biological stability, and anticoagulant activity of the G-modified TBA sequences. We found that the replacement of G into TBA sequences led to a remarkable improvement in the melting temperature up to 30 °C compared with the native sequence.

Linear consecutive hexaoxazoles as G4 ligands inducing chair-type anti-parallel topology of a telomeric G-quadruplex.

G-quadruplex structures (G4s) in guanine-rich regions of DNA play critical roles in various biological phenomena, including replication, translation, and gene expression. There are three types of G4 topology, , parallel, anti-parallel, and hybrid, and ligands that selectively interact with or stabilize a specific topology have been extensively explored to enable studies of topology-related functions. Here, we describe the synthesis of a new series of G4 ligands based on 6LCOs (6-linear consecutive oxazoles), , L2H2-2M2EA-6LCO (2), L2A2-2M2EAc-6LCO (3), and L2G2-2M2EG-6LCO (4), which bear four aminoalkyl, acetamidealkyl, and guanidinylalkyl side chains, respectively.

Oligonucleotides DNA containing 8-trifluoromethyl-2'-deoxyguanosine for observing Z-DNA structure.

Z-DNA is known to be a left-handed alternative form of DNA and has important biological roles as well as being related to cancer and other genetic diseases. It is therefore important to investigate Z-DNA structure and related biological events in living cells. However, the development of molecular probes for the observation of Z-DNA structures inside living cells has not yet been realized.

Telomeric DNA-RNA-hybrid G-quadruplex exists in environmental conditions of HeLa cells.

In the present study, we employed a F NMR approach to study the association of telomere RNA and DNA in vitro and in living human cells. We successfully characterized the DNA-RNA hybrid G-quadruplex (HQ) structure formed by telomeric DNA and RNA. We further demonstrated for the first time that an HQ conformation can exist in the environmental conditions of HeLa cells.

F NMR Spectroscopy for the Analysis of DNA G-Quadruplex Structures Using F-Labeled Nucleobase.

G-quadruplex structures have been suggested to be biologically important in processes such as transcription and translation, gene expression and regulation in human cancer cells, and regulation of telomere length. Investigation of G-quadruplex structures associated with biological events is therefore essential to understanding the functions of these molecules. We developed the F-labeled nucleobases and introduced them into DNA sequences for the F NMR spectroscopy analysis.

2'--Methyl-8-methylguanosine as a Z-Form RNA Stabilizer for Structural and Functional Study of Z-RNA.

In contrast to Z-DNA that was stabilized and well-studied for its structure by chemical approaches, the stabilization and structural study of Z-RNA remains a challenge. In this study, we developed a Z-form RNA stabilizer m⁸Gm, and demonstrated that incorporation of m⁸Gm into RNA can markedly stabilize the Z-RNA at low salt conditions. Using the m⁸Gm-contained Z-RNA, we determined the structure of Z-RNA and investigated the interaction of protein and Z-RNA.

In Situ Reduction from Uranyl Ion into a Tetravalent Uranium Trimer and Hexamer Featuring Ion-Exchange Properties and the Alexandrite Effect.

By utilizing zinc amalgam as an in situ reductant and pH regulator, mild hydrothermal reaction between UO(CHCOO)·2HO, HSO, and CsCO or between UO(CHCOO)·2HO, CH(SOH), and KCO yielded a novel cesium U sulfate trimer Cs[UO(SO)]·2.2HO (1) and a new potassium U disulfonic hexamer K[UO(OH)(HO)][CH(SO)]·6HO (2), respectively. Compound 1 features a lamellar structure with a honeycomb lattice, and it represents an unprecedented trimeric U cluster composed of purely inorganic moieties.

Investigation of higher-order RNA G-quadruplex structures in vitro and in living cells by F NMR spectroscopy.

Growing evidence indicates that RNA G-quadruplexes have important roles in various processes such as transcription, translation, regulation of telomere length, and formation of telomeric heterochromatin. Investigation of RNA G-quadruplex structures associated with biological events is therefore essential to understanding the functions of these RNA molecules. We recently demonstrated that the sensitivity and simplicity of F NMR can be used to directly observe higher-order telomeric G-quadruplexes of labeled RNA molecules in vitro and in living cells, as well as their interactions with ligands and proteins.

A multi-functional guanine derivative for studying the DNA G-quadruplex structure.

In the present study, we developed a multi-functional guanine derivative, G, as a G-quadruplex stabilizer, a fluorescent probe for the detection of G-quadruplex formation, and a F sensor for the observation of the G-quadruplex. We demonstrate that the functional nucleoside bearing a 3,5-bis(trifluoromethyl)benzene group at the 8-position of guanine stabilizes the DNA G-quadruplex structure and fluoresces following the G-quadruplex formation. Furthermore, we show that the functional sensor can be used to directly observe DNA G-quadruplexes by F-NMR in living cells.

Structure-Dependent Binding of hnRNPA1 to Telomere RNA.

Telomeric repeat-containing RNA is a new noncoding RNA molecule that performs various biofunctions. Heterogeneous nuclear ribonucleoprotein (hnRNP) A1 is an RNA-binding protein involved in the telomere maintenance machinery. To date, little is known about how hnRNPA1 binds to telomeric RNA.

Characterization of human telomere RNA G-quadruplex structures in vitro and in living cells using 19F NMR spectroscopy.

Human telomeric RNA has been identified as a key component of the telomere machinery. Recently, the growing evidence suggests that the telomeric RNA forms G-quadruplex structures to play an important role in telomere protection and regulation. In the present studies, we developed a 19F NMR spectroscopy method to investigate the telomeric RNA G-quadruplex structures in vitro and in living cells.

Direct Methylation of Amines with Carbon Dioxide and Molecular Hydrogen using Supported Gold Catalysts.

The N-methylation of amines with CO2 and H2 is an important step in the synthesis of bioactive compounds and chemical intermediates. The first heterogeneous Au catalyst is reported for this methylation reaction with good to excellent yields. The average turnover frequency (TOF) based on surface Au atoms is 45 h(-1) , which is the highest TOF value ever reported for the methylation of aniline with CO2 and H2 .

Photochemically engineering the metal-semiconductor interface for room-temperature transfer hydrogenation of nitroarenes with formic acid.

A mild photochemical approach was applied to construct highly coupled metal-semiconductor dyads, which were found to efficiently facilitate the hydrogenation of nitrobenzene. Aniline was produced in excellent yield (>99 %, TOF: 1183) using formic acid as hydrogen source and water as solvent at room temperature. This general and green catalytic process is applicable to a wide range of nitroarenes without the involvement of high-pressure gases or sacrificial additives.

Synergistic effect of Brønsted acid and platinum on purification of automobile exhaust gases.

The catalytic purification of automobile exhaust gases (CO, NOx and hydrocarbons) is one of the most practiced conversion processes used to lower the emissions and to reduce the air pollution. Nevertheless, the good performance of exhaust gas purification catalysts often requires the high consumption of noble metals such as platinum. Here we report that the Brønsted acid sites on the external surface of a microporous silicoaluminophosphate (SAPO) act as a promoter for exhaust gas purification, effectively cutting the loading amount of platinum in the catalyst without sacrifice of performance.