DNA Condensation with a Boron-Containing Cationic Peptide for Modeling Boron Neutron Capture Therapy.

The amino acid derivative 4-borono--phenylalanine (BPA) has been used in the radiation medicine technique boron neutron capture therapy (BNCT). Here we have characterized its interaction with DNA when incorporated into a positively charged hexa--arginine peptide. This ligand binds strongly to DNA and induces its condensation, an effect which is attenuated at higher ionic strengths.

Damage clusters after gamma irradiation of a nanoparticulate plasmid DNA peptide condensate.

We have gamma-irradiated plasmid DNA in aqueous solution in the presence of submillimolar concentrations of the ligand tetra-arginine. Depending upon the ionic strength, under these conditions, the plasmid can adopt a highly compacted and aggregated form which attenuates by some two orders of magnitude the yield of damage produced by the indirect effect. The yields of DNA single- and double-strand breaks (SSB and DSB) which result are closely comparable with those produced in living cells.