A correlation between the secondary structure of DNA and the reactivity of adenine residues with chloroacetaldehyde.
The rate of reaction of chloroacetaldehyde (0.039 M) with the "free" adenine residue in deoxyadenosine-5'-phosphate (dAMP) at pH 6.5 has been found to be nearly equal to that at pH 4.5. Practically 100% of the adenine is converted to a fluorescent product (epsilon-adenine residue) on incubation for 60 h at 37 degrees C and pH 6.5. Of the adenine residues in "single-stranded" DNA, however, only 14% react with chloroacetaldehyde (0.039 M) under the same incubation conditions. The reaction rate of this 14% is nearly equal to that of dAMP, but the fluorescence of the product is appreciably quenched; the quantum yield is only 0.45 times that of the "free" adenine residue. In "double-helical" DNA, on the other hand, no adenine residue has been found to react with chloracetaldehyde. Possible application of these findings to structural studies of DNA is suggested.
D000079:Acetaldehyde / Q000031:analogs & derivatives*; D000225:Adenine; D004247:DNA; D004277:DNA, Single-Stranded; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009690:Nucleic Acid Conformation; D012313:RNA; D013696:Temperature
D004277:DNA, Single-Stranded; D012313:RNA; D004247:DNA; D000079:Acetaldehyde; D000225:Adenine