Design of peptide that recognizes double-stranded DNA.

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 lambda phage CRO repressor (CRO). The designed peptides contain helix-turn-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.