The equilibrium association constant observed for many DNA-protein interactions in vitro (K(obs)) is strongly dependent on the salt concentration of the reaction buffer ([MX]). This dependence is often used to estimate the number of ionic contacts between protein and DNA by assuming that release of cations from the DNA is the dominant involvement of ions in the binding reaction. With this assum...

The interaction of chitosan with plasmid DNA was investigated as a function of pH, buffer composition, degree of deacetylation (DDA), and molecular weight (M(n)) of chitosan, using isothermal titration microcalorimetry (ITC). The Single Set of Identical Sites model was used to obtain the enthalpy of interaction, the binding constant, and the stoichiometry of binding. The chitosan-DNA interactio...

Molecular recognition and chemical modification of DNA are important in medicinal chemistry, toxicology, and biotechnology. Historically, natural products have revealed many interesting and unexpected mechanisms for noncovalent DNA binding and covalent DNA modification. The studies reported here characterize the molecular mechanisms underlying the efficient alkylation of duplex DNA by the Strep...

The interaction of proflavine with herring sperm DNA has been investigated by cyclic voltammetry and UV-Vis spectroscopy as well as viscosity measurements. Shifts in the peak potentials in cyclic voltammetry, spectral changes in UV absorption titration, an increase in viscosity of DNA and the results of the effect of ionic strength on the binding constant strongly support the intercalation of p...

The pairing of single- and double-stranded DNA molecules at homologous sequences promoted by recA and single-stranded DNA-binding proteins of Escherichia coli follows apparent first-order kinetics. The initial rate and first-order rate constant for the reaction are maximal at approximately 1 recA protein/3 and 1 single-stranded DNA-binding protein/8 nucleotides of single-stranded DNA. The initi...

The precursor to adenovirus protein VI, pVI, is a multifunctional protein with different roles early and late in virus infection. Here, we focus on two roles late in infection, binding of pVI to DNA and to the major capsid protein hexon. pVI bound to DNA as a monomer independent of DNA sequence with an apparent equilibrium dissociation constant, K(d)((app)), of 46 nm. Bound to double-stranded D...

The effects of allopurinol, acyclovir and theophylline on the activity of adenosine deaminase (ADA) were studied in 50 mM sodium phosphate buffer pH 7.5 at 27°C, using a UV– Vis spectrophotometer. Adenosine deaminase is inhibited by these ligands, via different types of inhibition. Allopurinol, as a transition state analog of xanthine oxidase, and acyclovir competitively inhibit the catalytic a...

The effects of allopurinol, acyclovir and theophylline on the activity of adenosine deaminase (ADA) were studied in 50 mM sodium phosphate buffer pH 7.5 at 27°C, using a UV– Vis spectrophotometer. Adenosine deaminase is inhibited by these ligands, via different types of inhibition. Allopurinol, as a transition state analog of xanthine oxidase, and acyclovir competitively inhibit the catalytic a...

Hydrogen titanate nanotubes were synthesized by hydrothermal process using 10 M NaOH and TiO2 anatase powder. The material synthesized was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to ensure the structural and morphological characteristics. The interaction of calf thymus DNA (CT-DNA) and bovine serum albumin protein w...

Fluorescence anisotropy and fluorescence correlation spectroscopy measurements of rhodamine-labeled DNA oligonucleotide duplexes have been used to determine equilibrium binding constants for DNA binding of the prokaryotic transcription activator protein NtrC. Measurements were made with wild-type NtrC from Escherichia coli and the constitutively active mutant NtrCS160Ffrom Salmonella using DNA ...