Specifically alkylated DNA fragments. Synthesis and physical characterization of D[cGC(o2Me)GCG]and D[cGT(o6Me) GCG]

Abstract

Two hexamer DNA fragments containing a carcinogenic modified base, 06-methyl guanine, have been synthesized by a solid-phase phosphotriester method, in which the unmodified guanine residues present were 0o protected with the 4-nitrophenylethyl group. These two alkylated oligonucleotides were found to have similar Tm's about 40o lower than the unmodified parent compound, d(CG)3. Moreover, the presence of the (06Me)G appears to inhibit the B+Z transition, as determined by CD spectroscopy © 1983 IRL Press Limited.