Purified Escherichia coli recA protein catalyzed ATP-dependent pairing of superhelical DNA and homologous single-stranded fragments. The product of the reaction: (i) was retained by nitrocellulose filters in 1.5 M NaCl/0.15 M Na citrate at pH 7, (ii) was dissociated at pH 12.3 but was not dissociated by heating at 55 degrees C for 4 min or by treatment with 0.2% sodium dodecyl sulfate and prote...

This study reports the hybridization kinetics of double-stranded DNA probes for rapid molecular analysis. Molecular binding schemes based on double-stranded DNA probes have been developed for quantitative detection of various biomolecules, such as nucleic acids and DNA binding proteins recently. The thermodynamic competition between the target and the competitor in binding to the probe provides...

Structural and functional properties of double stranded deoxyribonucleic acid (dsDNA) are investigated by atomic force microscopy (AFM) on a single molecule level. Here, we characterize different linear and circular DNA systems in terms of their geometry and topology, and visualize enzyme binding of restriction endonuclease Hae III to DNA. Manipulation of single DNA molecules is demonstrated by...

aptamers, or single stranded oligonucleotides, are produced by systematic evolution of ligands by exponential enrichment, abbreviated as selex. in the amplification and regeneration step of selex technique, dsdna is conversed to ssdna. asymmetric pcr is one of the methods used for the generation of ssdna. the purpose of this study was to design a random dna library for selection of aptamers wit...

The introduction of polymerase chain reaction (PCR) into the forensic field has greatly extended the ability to analyze DNA from small or degraded samples. However, one significant problem with PCR analysis is the sensitivity of Taq Polymerase to inhibitors found in many substrates commonly encountered with evidentiary materials. We hypothesize that the most problematic of these compounds inter...

In mammalian cells, double-strand break repair and V(D)J recombination require DNA-dependent protein kinase (DNA-PK), a serine/threonine kinase that is activated by DNA. DNA-PK consists of a 460-kDa subunit (p460) that contains a putative kinase domain and a heterodimeric subunit (Ku) that binds to double-stranded DNA ends. Previous reports suggested that the activation of DNA-PK requires the b...

Understanding the patterns of noncovalent adsorption double-stranded nucleic acids (dsDNA) on gold nanoparticles (GNPs) was aim this study. It found that high-affinity motifs in DNA can and do act as an “anchor” for fixation whole molecule GNP (up to 98 ± 2 single-stranded (ss)DNA molecules per particle with diameter 13 nm). At same time, involvement intramolecular interaction negatively affect...