The study of DNA-protein interactions is of great importance to understand basic cellular processes such as transcription, replication and recombination. In this research, we developed a novel detection system for DNA-binding proteins (DBPs) involving the exonuclease (Exo) III and Taq DNA polymerase reactions. The system consists of three steps, as follows: the target DBP in the sample solution is incubated with probe DNA, and the probe is digested with Exo III and then extended with Taq using fluorescent dye-labeled dUTP as a substrate. The DBP protects the probe from digestion by Exo III. Therefore, only the DBP-bound probe allows the following extension. We examined this system using the lambda phage Cro repressor in a homogeneous format. The fluorescence image after gel electrophoresis showed a specific band. We also found that this system could be applied to the rapid and efficient detection of DBPs in stem and loop ds-DNA array formats. These results suggest that our method is useful as a new tool for analyzing DNA-protein interactions.
A novel molecular tool for double-stranded (ds) DNA detection using synthetic peptide is described. The peptide was designed based on the DNA binding domain of the λ phage CRO repressor (CRO). The designed peptides contain helixturn-helix (HTH), which is DNA binding motif. A cyclic peptide and a mutant peptide based on CRO were also designed, and the resulting affinity for dsDNA was increased. Furthermore, native amino acids of the peptide were replaced with arginine to increase the affinity for dsDNA. The affinity of these peptides for DNA binding was assessed by surface plasmon resonance (SPR) technique.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.