title: Specifically alkylated DNA fragments. Synthesis and physical characterization of d[CGC(O6Me)GCG] and d[CGT(O6Me)GCG].
abstract: Two hexamer DNA fragments containing a carcinogenic modified base, O6-methyl guanine, have been synthesized by a solid-phase phosphotriester method, in which the unmodified guanine residues present were O6 protected with the 4-nitrophenylethyl group. These two alkylated oligonucleotides were found to have similar Tm's about 40 degrees lower than the unmodified parent compound, d(CG)3. Moreover, the presence of the (O6Me)G appears to inhibit the B leads to Z transition, as determined by CD spectroscopy.
mesh_terms: D001483:Base Sequence; D002942:Circular Dichroism; D004247:DNA; D006147:Guanine / Q000031:analogs & derivatives; D007202:Indicators and Reagents; D008745:Methylation; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis*; D009841:Oligonucleotides / Q000138:chemical synthesis*; D013329:Structure-Activity Relationship; D013696:Temperature
chemical_list: D007202:Indicators and Reagents; D009838:Oligodeoxyribonucleotides; D009841:Oligonucleotides; D006147:Guanine; D004247:DNA; C008449:O-(6)-methylguanine