Molecular assembling of DNA with amphipathic peptides

The self-assembling of double-stranded DNA with short synthetic peptides has been analysed using the fluorescent properties of the intercalating dye, ethidium bromide, Two membrane-active peptides with appropriate sequences of lysine and leucine amino acids and a short polylysine have been probed, The results revealed that the secondary structure of the peptide decisively aimed the peptide-DIVA complex formation: only the longest peptide, which is the only one to exhibit an cl-helical structure in solution, could achieve DNA compacting before charge neutralisation, The obtained complex retained a significant membrane activity as demonstrated by calcein leakage experiments, This shows that short synthetic peptides of elementary sequence can combine both membrane activity and DNA-condensing properties, The potential of these constructs as DNA carriers will be discussed, (C) 1998 Federation of European Biochemical Societies.