Use of Capillary Electrophoresis in the Study of Interaction between dsDNA and Drug Molecules

The advantages of berberine such as the anticancer1, antiinflammatory2 and no side effects of camptothecin1, have promoted the research in the mechanism of berberine with macrobiomolecules. In general, three different points of view have been presented on…     

Shape-controllable Synthesis of Functional Nanomaterials on DNA Templates

DNA nanotechnology enables precise organization of nanoscale objects with extraordinarily structural programmability.Self-assembled DNA nanostructures possess a lot of interesting features,such as designable size and shape,and structural addressability at nanometer scale.Taking advantage of these properties,DNA nanostructures could work as templates or molds for the controllable synthesis of functional nanomaterials,such as organic macromolecules,metallic or inorganic nonmetallic nanomaterials.In this review,we summarize the recent progress in the shape-controllable synthesis of functional nanomaterials on DNA templates.The potential application fields of these nanomaterials are also discussed.     

Antitumour Activity of Chitosan Hydrogen Selenites

Selenium is a biologically important element and essential for life1. Selenium deficiency causes severe degenerative disease, such as Kesan cardiomyopathy, and has been implicated in increasing the incidence of human cancer and some chronic ailment as well as ageing. Administration of selenium compounds such as sodium selenite protects animals against carcinogens and markedly reduces the incidence of various neoplasms in human2. Chitosan is one of the most abundant glycans in nature and its…     

Theoretical study of the intermolecular hydrogen bond interaction for furan-HCl and furan-CHCl_3 complexes

The importance of intermolecular interactions in biology and material science has prompted chemists to explore the nature of the variety of such interactions. The strongest of these interac-tions are the hydrogen bonds, which play an important role in determining the molecular confor-mation, crystal packing, and the structure of biological systems such as nucleic acids. Extensive experimental and theoretical efforts[1—5] have been devoted to the studies of this type of interac-tions, such as …     

A New Method for Determination of Adsorption and Desorption Coefficients of Pesticides with Soil Column Liquid Chromatography

Agricultural chemicals such as pesticides were extensively applied in the fields. Pesticides effectively protect the crops, only as long as they remain in the root zone of soil. In case a portion of the chemicals leaves root zone and especially leaches through soil pores. They may pollute groundwater and be a serious environmental problem1. This problem has got widespread concern in the world. In soils the fate of organic compounds such as pesticides is governed by hydraulic transport coupled…     

Synthesis and Crystal Structure of a New Ternary Mixed Ligand Complex [Cu（ampym）（bapa）Cl]（ClO4） （ampym = 2-Aminopyrimidine, bapa = Bi（3-aminopropyl）amine）

1 INTRODUCTION The pyrimidine substructure plays a vital role in physiological system. It occurs not only in organisms such as nucleic acids, vitamins and coenzymes[1~3], but also frequently presents in commercially availa- ble drugs such as antibiotics, antiatherosclerotic and antihypertensive agent[4, 5]. Studying the interaction of pyrimidine derivatives and metal ions is important as a means of understanding the role of pyrimidine ring in biological systems. This paper describes the …     

Microwave-assisted reaction of peptide formation by amino acid with phosphate:Exploration of the most possible channels for the origin of life

The formation of peptides and then protein by small abiological molecules clusters such as amino acid is a key stage in the origin of life[1]. More and more ex- perimental results showed that phosphate plays an important role in the formation of biomolecules in prebiotic chemical evolution. The principal reservoirs of biochemical energy are phosphates (such as ATP). The peculiar role of phosphates in contemporary life might suggest its essential role in prebiotic energy conversion, syntheses …     

A Novel Two-dimensional Layer Compound Built up by Hexapolyoxotungstates and Coordinated Sodium Chains

1 INTRODUCTION There has been extensive interest in the synthesis of heteroxometallates owing to their fascinating pro- perties and great potential applications in many fields, such as catalysis, material science, medicine and magnetochemistry as well as their unusual topo- logical properties[1～4]. Although various preparation methods have been proposed for the preparation of such materials, to find new synthetic method for novel compounds in this field is still one of the major chal- le…     

Transformation of Oximes and Alcohols to Carbonyl Compounds Using Amberlite IRA-400 Supported Chromic Acid in the Presence of Zirconium Tetrachloride

A wide variety of oximes and alcohols were efficiently converted to their corresponding aldehydes and ketones in good to excellent yields using amberlite IRA-400 supported chromic acid in the presence of zirconium tetrachloride in refluxing acetonitrile-H2O. Selective oxidation of oximes and alcohols in the presence of other functional groups such as acetal, hydrazone, aldehyde, ether and alkene can be considered as a noteworthy advantage of this method. A wide variety of oximes and alcohols were efficiently converted to their corresponding aldehydes and ketones in good to excellent yields using amberlite IRA-400 supported chromic acid in the presence of zirconium tetrachloride in refluxing acetonitrile-H2O. Selective oxidation of oximes and alcohols in the presence of other functional groups such as acetal, hydrazone, aldehyde, ether and alkene can be considered as a noteworthy advantage of this method.     

Synthesis and Crystal Structure of CoCl（ieaa）（C10H7—ieai）（C10H7NH2）

1 INTRODUCTION A number of isonitroso-b-diketones and isonitroso-b-ketoesters such as isonitrosoacetyl- acetone(Hiaa), isonitrosobenzoylacetone(Hiba) and isonitrosoethylacetoacetate (Hieaa) have been employed as reagents in spectrophotometric determination of iron, palladium and ruthenium[1]. Transition metal complexes of such ligands[2] are potential models for metal binding sites in ferroverdin[3]. They were found as dyes and light-absorbing agents for the acceleration of the sol…     

Studies of interaction between a new synthesized minor-groove targeting artificial nuclease and DNA

Nuclease plays an important role in molecular biology, such as DNA sequencing. Synthetic polyamide conjugates can be considered as new tool in the selective inhibition of gene expression and as potential drugs in anticancer or antiviral chemotherapy. In this paper, a new synthesized minor-groove targeting artificial nuclease, oligopyrrol-containing peptide, was reported. It was found that this new compound can bind DNA in AT-riched minor groove with high affinity and site specificity. DNA binding behavior was determined by UV-vis and circular dichroism (CD) methods. It was indicated that compound 6 can enhance the Tm of oligomer DNA from 51.8 to 63.5 degrees C and possesses large binding constant (Kb=8.83x10(4)L/mol).     

Synthesis of a novel fluorescent probe and investigation on its interaction with nucleic acid and analytical application

A novel fluorescent probe N-(N-(2-(4-morpholinyl)ethyl)-4-acridinecarboxamide)-alpha-alanine (N-(N-(ME)-4-ACA)-alpha-ALA) was synthesized. The structure was characterized by 1H NMR, MS, elemental analysis, fluorescent and ultraviolet spectra. This new compound exhibited high binding affinity to DNA, intense fluorescence and high water solubility. Experiment indicated that the fluorescent intensity was quenched when DNA was added. A method for DNA determination based on the quenching fluorescence (lambda(ex)=258nm, lambda(em)=451nm) of N-(N-(ME)-4-ACA)-alpha-ALA was established. Under optimal conditions (pH 7.2, CN-(N-(ME)-4-ACA)-alpha-ALA)=3 x 10(-6) mol L(-1)), the linear range is 0.1-4.0 microg mL(-1) for both fish semen (fsDNA) and calf thymus DNA (ct-DNA). The corresponding determination limits are 4.6 ng mL(-1) for fsDNA and 5.1 ng mL(-1) for ct-DNA, respectively. The relative standard deviation is 1.0%. Thus this compound can be used as a DNA fluorescent probe. The experiments proved that the interaction mode between N-(N-(ME)-4-ACA)-alpha-ALA and DNA was groove binding. The modified Rosenthal's graphical method gave the binding constant of 1.0 x 10(6) L mol(-1) and a binding size of 0.31 base pairs per bound drug molecule.     

A rationally designed genotoxin that selectively destroys estrogen receptor-positive breast cancer cells

We describe a novel strategy to increase the selective toxicity of genotoxic compounds. The strategy involves the synthesis of bifunctional molecules capable of forming DNA adducts that have high affinity for specific proteins in target cells. It is proposed that the association of such proteins with damaged sites in DNA can compromise protein function and/or DNA repair resulting in increased toxicity. We describe the synthesis of a bifunctional compound consisting of an aniline mustard linked to the 7alpha position of estradiol. This novel compound can form covalent DNA adducts that have high affinity for the estrogen receptor. Breast cancer cells that express high levels of the estrogen receptor showed increased sensitivity to the cytotoxic effects of the new compound.     

Poly-intercalators Carrying Threading Intercalator Moieties as Novel DNA Targeting Ligands

Threading intercalators are a novel class of intercalators that carry two substituents along the diagonal positions of an aromatic ring. These substituents are projecting out in DNA grooves when bound to DNA. Poly-intercalators carrying threading intercalating parts are quite novel and were recently found to show a unique DNA binding behavior. We review herein two types of poly-intercalators. First, tris-intercalators carrying a threading intercalator part in the middle of the molecule are described. These intercalators appear to intercalate into double stranded DNA in a special binding manner, which we call the penetrating mode, in which all the three intercalating units are arranged linearly with one of them penetrating into the DNA ladder. We synthesized two tris-intercalators ( 3 and 4) of this type and studied their binding behavior for double stranded DNA. All the experimental results were consistent with the proposed penetrating mode. Another type of threading poly-intercalators is a macrocyclic bis-threading intercalator ( 5). We found that this compound can bis-intercalate to double stranded DNA when the base pairing is disrupted temporarily to form a complex with a unique structure like a catenane. On the basis of a study of the interaction of such intercalators we envisage that DNA is a flexible and dynamic entity. These novel families of poly-intercalators will expand the scope of DNA poly-intercalation chemistry with possible medicinal applications.     

A novel cationic triazatetrabenzcorrole: selective detection of mercury(II) by nucleic acid-induced aggregation

In the present work, a novel water-soluble cationic triazatetrabenzcorrole compound was synthesised. Its aggregation and fluorescence quenching properties are demonstrated by serval methods, such as UV-vis and fluorescence spectroscopic studies and naked-eye visualization. Unlike the traditional Hg(2+) sensor based on thymine-Hg(2+)-thymine, we use a novel approach, exploiting the high affinity of Hg(2+) for sulfur in phosphorothioate DNA. Based on the S-Hg(2+)-S pairs, we designed the phosphorothioate DNA T4G4-S3 as an Hg(2+) sensor, which can detect Hg(2+) sensitively and selectively in aqueous solution. And this sensing system is fairly fast and convenient.     

一种新型发光探针与DNA相互作用的研究

本文以稳态荧光光谱、紫外-可见吸收光谱、荧光偏振、热变性、阴离子猝灭等手段,研究了一种具有强电荷转移能力的化合物2,7-二[(N-乙基咔唑-3-基)丙烯-1-酮基]芴与DNA的相互作用。研究结果表明,2,7-二[(N-乙基咔唑-3-基)丙烯-1-酮基)芴与DNA的作用方式是混合模式,以嵌插作用为主,同时存在沟槽相互作用,其咔唑基团可能插入到DNA的碱基对之间,结合常数K为8 123.48mol/L,结合位点n为0.71。该发光探针灵敏度高,结合稳定。     

Synthesis of a novel fluorescent probe based on acridine skeleton used for sensitive determination of DNA

In this study, a novel fluorescent probe of acridine derivative N-((N-(2-dimethylamino)ethyl)acridine-4-carboxamide)-alpha-alanine (N-(ACR-4-CA)-alpha-ALA) was synthesized. The structure of the new compound was characterized by (1)H NMR, MS, elemental analysis, fluorescent and ultraviolet spectra. It was found that DNA had the ability to quench the fluorescence of N-(ACR-4-CA)-alpha-ALA, and the quenched intensity of fluorescence was proportional to the concentration of DNA. A method for DNA determination based on the quenching fluorescence (lambda(ex) = 260 nm, lambda(em) = 451 nm) of N-(ACR-4-CA)-alpha-ALA was established. Under optimal conditions, the linear range is 0.05-2.0 microg mL(-1) for both fish semen (fsDNA) and calf thymus DNA (ctDNA). The corresponding determination limits are 9.1 ng mL(-1) for fsDNA and 8.7 ng mL(-1) for ctDNA, respectively. The results suggested that the interaction mode between N-(ACR-4-CA)-alpha-ALA and DNA was intercalative binding. The intrinsic binding constant was determined and the result showed a large binding constant of N-(ACR-4-CA)-alpha-ALA with DNA.     

Arrest of Rolling Circle Amplification by Protein‐Binding DNA Aptamers

Certain DNA polymerases, such as ?29 DNA polymerase, can isothermally copy the sequence of a circular template round by round in a process known as rolling circle amplification (RCA), which results in super‐long single‐stranded (ss) DNA molecules made of tandem repeats. The power of RCA reflects the high processivity and the strand‐displacement ability of these polymerases. In this work, the ability of ?29DNAP to carry out RCA over circular templates containing a protein‐binding DNA aptamer sequence was investigated. It was found that protein–aptamer interactions can prevent this DNA polymerase from reading through the aptameric domain. This finding indicates that protein‐binding DNA aptamers can form highly stable complexes with their targets in solution. This novel observation was exploited by translating RCA arrest into a simple and convenient colorimetric assay for the detection of specific protein targets, which continues to showcase the versatility of aptamers as molecular recognition elements for biosensing applications.     

Novel Dual‐Site‐Binding Neuraminidase Inhibitor from Virtual Screening by Pharmacophore and Molecular Dynamics Methods

Neuraminidase is a significant anti‐influenza target that plays crucial role in virus replication cycle. The discovery of 150‐cavity in Group‐1 neuraminidase provides us a novel mentality of designing inhibitor which can bind with both conserved site and 150‐cavity. In order to discover novel dual‐site‐binding inhibitors, a 3D chemical‐feature‐based pharmacophore model was established to cover dual‐site in neuraminidase. The dual‐site‐binding model was consistent in predicting the binding conformation of Group‐1 neuraminidase inhibitor and applied for virtual screening of Specs database. Compound 4 (ZINC05790048) that aligned well to the model was selected after multiple filtrations for molecular dynamics simulations, indicating improved binding energy with neuraminidase. It can sever as the lead compound for a novel series of inhibitors.