2009 年 67 巻 7 号 p. 680-687
Nucleic acids often acquire new functions by forming a variety of complexes with metal ions. Osmium, in an oxidized state, also reacts with C5-methylated pyrimidines in the presence of bipyridine to give a stable ternary complex. We have designed a bipyridine-attached adenine derivative for sequence-specific osmium complexation. Sequence-specific osmium complexation was achieved by hybridization of a short DNA molecule containing this functional nucleotide to a target DNA sequence, and resulted in the formation of a crosslinked structure. The interstrand crosslink clearly distinguished methylated cytosines from unmethylated cytosines, and was used to quantify the degree of methylation at a specific cytosine in the genome.