N-Sulfomethylation of guanine, adenine and cytosine with formaldehyde-bisulfite. A selective modification of guanine in DNA

摘要

When guanine-, adenine- and cytosine-nucleosides and nucleotides were treated with formaldehyde and then with bisulfite, stable N-sulfomethyl compounds were formed. N2-Sulfomethyl guanine, N6-sulfomethyladenine, N4-sulfomethylcytosine and N6-sulfomethyl-9-β-D-arabinofuranosyladenine were isolated as crystals and characterized. A guanine-specific sulfomethylation was brought about by treatment of denatured single-stranded DNA with formaldehyde and then with bisulfite at pH 7 and 4°C.Since native double-stranded DNA was not modified by this treatment, this new method of modification is expected to be useful as a conformational probe for polynucleotides.