Fluorescence study of secondary structure of DNA within bacteriophage λ

Bromoacetaldehyde (BAA) was used to study the secondary structure of DNA in λ-phage particles. It was determined that about 1% of the adenines in the intraphage λ-DNA reacts readily with BAA, thus, they are placed in DNA sites with disturbed complementary interactions. These adenines are close to the tryptophan residues of the phage protein. Fluorescence emission of ϵA in the intraphage DNA is dramatically quenched. This, apparently, indicates the interaction between ϵA and Trp- and/or Tyr- and/or Met-residues of phage protein.