15] Adenine-specific DNA chemical sequencing reaction

Abstract

DNA sequence determination according to the method of Maxam and Gilbert utilizes base-specific chemical modification reactions followed by a workup that causes cleavage of the sugar-phosphate backbone at the site of the modified base. Reactions have been reported that are capable of selective cleavage of DNA at G, G + A, A > G, A > C, C, C + T, and T residues. We describe here a simple protocol specific for adenine (A) that may be a useful addition to current chemical sequencing reactions. Reaction of DNA with K_2PdC1_4 at pH 2.0 followed by heating in the presence of piperidine produces an A-specific DNA cleavage reaction. The K_2PdCI_4 reaction involves selective depurination at adenine, affording an excision reaction analogous to the other chemical DNA sequencing reactions.