THE USE OF 2-HYDROPEROXYTETRAHYDROFURAN AS A REAGENT TO SEQUENCE CYTOSINE AND TO PROBE NON-WATSON-CRICK DNA STRUCTURES

2-Hydroperoxytetrahydrofuran (THF-OOH) can be employed to sequence cyt osine (C) and to probe for non-canonical DNA structures involving C, U sing P-32-labeled oligomers and a DNA restriction fragment, it is demo nstrated that THF-OOH has a strong preference for Cs in single-strande d (s-s) DNA regions, and in bulges, loops and mismatches, The reactivi ty of C is diminished below pH 6.0, but is not affected by substitutio n of 5-methylcytosine. To demonstrate the utility of the reagent, it i s directly compared to methoxylamine and chloroacetaldehyde, two other reagents commonly used to chemically probe C residues in non-Watson-C rick DNA structures.