Nonspecificity induces chiral specificity in the folding transition of giant DNA.

The all-or-none type DNA folding transition from a coil to globule can be differentiated by the chirality of the triamines. The fluorescent microscope observation on single DNA molecules makes it clear that the tripeptides obtained from naturally occurring basic amino acids (l-lysine or l-arginine) can compact DNA molecules at concentrations lower than those from d-isomers. Nanometer-sized beads are found in the AFM images on the folded DNA molecule.