Metabonomics analysis of the urine of rats with Qi deficiency and blood stasis syndrome has been performed by comparison with those of normal rats based on NMR techniques. The relative contents of formate,creatinine,2...Metabonomics analysis of the urine of rats with Qi deficiency and blood stasis syndrome has been performed by comparison with those of normal rats based on NMR techniques. The relative contents of formate,creatinine,2-oxoglutarate(2-OG) ,citrate,taurine,trimethylamine-N-oxide(TMAO) ,succinate and hippurate in the urine of the rats with Qi deficiency and blood stasis syndrome have been changed. These results have provided evidence for understanding the mechanism and the therapy of Qi defi-ciency and blood stasis syndrome.展开更多
G-rich single-stranded DNA (5′-TTAG-GG-3′) adopted a G-quadruplex structure in buffercontaining potassium ions. The spectroscopic featureand the interaction between methylene blue andG-quadruplex have been investiga...G-rich single-stranded DNA (5′-TTAG-GG-3′) adopted a G-quadruplex structure in buffercontaining potassium ions. The spectroscopic featureand the interaction between methylene blue andG-quadruplex have been investigated by circular di-chroism, and nuclear magnetic resonance spectros-copy. The UV-Vis absorption and fluorescence spec-tral results show that the fluorescence behavior ofMB by single-stranded DNA fits Stern-Volmer staticquenching equation very well and they formed 1︰1complexes; dimeric G-quadruplexes were bound toMB with 1︰1 or 2︰1, and their equilibrium constantswere 1.047×105 and 8.79×104 L/mol, respectively.Based on the above results and 1H-NMR spectraldata, one may conclude that MB stacked either theterminal tetrads to form 1︰1 complexes or betweentwo terminal tetrads of G-quadruplexes to form 1︰2sandwich complexes with G-qudruplexes.展开更多
Over the past few decades, numerous molecules have been discovered or designed to interact efficiently and selectively with a peculiar DNA structure named G-quadruplex. Some of these molecules have been developed as a...Over the past few decades, numerous molecules have been discovered or designed to interact efficiently and selectively with a peculiar DNA structure named G-quadruplex. Some of these molecules have been developed as anticancer agents. To aid the design of anticancer agents, the ability of alkaloids possessing Protoberberine and Benzophenanthridine groups to induce the formation of G-quadruplexes were studied using CD spectroscopy. By careful examination of their structures, we found that a benzo[1,3]dioxole group plays an important role in influencing their inductive properties. The more functional groups the alkaloids have, the stronger their G-quadruplex inductive ability.展开更多
G-quadruplexes attract more and more attention in recent years.Numerous small molecules which can induce or stabilize the formation of G-quadruplexes have been investigated on the purpose of anticancer drug developmen...G-quadruplexes attract more and more attention in recent years.Numerous small molecules which can induce or stabilize the formation of G-quadruplexes have been investigated on the purpose of anticancer drug development.As a motif existed in physiological condition,flanking sequences are an important part of G-quadruplexes but the study on the impact of flanking sequences on (G-quadruplex)-ligand binding is rarely reported.In this paper,the effects of flanking sequences on binding affinity between a series of unimolecular parallel-stranded G-quadruplex sequences derived from c-myc oncogene promoter (termed as c-myc G-quadruplexes) and their ligands are discussed in detail.The results showed that the flanking sequences on c-myc G-quadruplexes play key roles in (G-quadruplex)-ligand interaction.When a c-myc G-quadruplex is bound to its ligands,the flanking sequences might form a binding cavity above the terminal G-quartet,which could provide a suitable site for ligands to dock in.Moreover,the bases on flanking sequences could interact with ligand through π-π stacking,and finally form a sandwich-stacking mode (terminal G-quartet,ligand and bases on the flanking sequence).This mode could stabilize the (G-quadruplex)-ligand complex effectively and enhance the binding affinity dramatically.However,flanking sequences are also found to exhibit steric hindrance effect which could impede the (G-quadruplex)-ligand binding.展开更多
文摘Metabonomics analysis of the urine of rats with Qi deficiency and blood stasis syndrome has been performed by comparison with those of normal rats based on NMR techniques. The relative contents of formate,creatinine,2-oxoglutarate(2-OG) ,citrate,taurine,trimethylamine-N-oxide(TMAO) ,succinate and hippurate in the urine of the rats with Qi deficiency and blood stasis syndrome have been changed. These results have provided evidence for understanding the mechanism and the therapy of Qi defi-ciency and blood stasis syndrome.
文摘G-rich single-stranded DNA (5′-TTAG-GG-3′) adopted a G-quadruplex structure in buffercontaining potassium ions. The spectroscopic featureand the interaction between methylene blue andG-quadruplex have been investigated by circular di-chroism, and nuclear magnetic resonance spectros-copy. The UV-Vis absorption and fluorescence spec-tral results show that the fluorescence behavior ofMB by single-stranded DNA fits Stern-Volmer staticquenching equation very well and they formed 1︰1complexes; dimeric G-quadruplexes were bound toMB with 1︰1 or 2︰1, and their equilibrium constantswere 1.047×105 and 8.79×104 L/mol, respectively.Based on the above results and 1H-NMR spectraldata, one may conclude that MB stacked either theterminal tetrads to form 1︰1 complexes or betweentwo terminal tetrads of G-quadruplexes to form 1︰2sandwich complexes with G-qudruplexes.
文摘Over the past few decades, numerous molecules have been discovered or designed to interact efficiently and selectively with a peculiar DNA structure named G-quadruplex. Some of these molecules have been developed as anticancer agents. To aid the design of anticancer agents, the ability of alkaloids possessing Protoberberine and Benzophenanthridine groups to induce the formation of G-quadruplexes were studied using CD spectroscopy. By careful examination of their structures, we found that a benzo[1,3]dioxole group plays an important role in influencing their inductive properties. The more functional groups the alkaloids have, the stronger their G-quadruplex inductive ability.
文摘G-quadruplexes attract more and more attention in recent years.Numerous small molecules which can induce or stabilize the formation of G-quadruplexes have been investigated on the purpose of anticancer drug development.As a motif existed in physiological condition,flanking sequences are an important part of G-quadruplexes but the study on the impact of flanking sequences on (G-quadruplex)-ligand binding is rarely reported.In this paper,the effects of flanking sequences on binding affinity between a series of unimolecular parallel-stranded G-quadruplex sequences derived from c-myc oncogene promoter (termed as c-myc G-quadruplexes) and their ligands are discussed in detail.The results showed that the flanking sequences on c-myc G-quadruplexes play key roles in (G-quadruplex)-ligand interaction.When a c-myc G-quadruplex is bound to its ligands,the flanking sequences might form a binding cavity above the terminal G-quartet,which could provide a suitable site for ligands to dock in.Moreover,the bases on flanking sequences could interact with ligand through π-π stacking,and finally form a sandwich-stacking mode (terminal G-quartet,ligand and bases on the flanking sequence).This mode could stabilize the (G-quadruplex)-ligand complex effectively and enhance the binding affinity dramatically.However,flanking sequences are also found to exhibit steric hindrance effect which could impede the (G-quadruplex)-ligand binding.
