Chemical cleavage sequencing of DNA using matrix-assisted laser desorptionionization time-of-flight mass spectrometry

In this paper, we report for the first time use of laser desorption mass sp ectrometry for measurement of chemical cleavage sequencing products of DNA. Tn this method, the target DNA was labeled with biotin and subjected to ch emical modification and cleavage according to the Maxam-Gilbert sequencing protocol. The biotin-containing fragments were captured by streptavidin-coa ted magnetic beads and separated from the other fragments. The captured fra gments were released by hot ammonia treatment, and the released fragments w ere analyzed by mass spectrometry. Potential applications of this method in resolving sequence ambiguities and sequencing repeat sequences as well as in the analysis of DNA-protein interactions are discussed.