Figure 3. Site-specific detection of DNA methylation with a MercuLock.

(a) through (d) were current traces for the bisufite-converted T_p16-1 hybridized with probes P_C6 (a), P_C8 (b), P_C14 (c) and P_C16 (d) in the absence of Hg²⁺ (left panel) and in the presence of Hg²⁺ (right panel ). The four probes were designed for detecting CpG cytosines at the positions C6, C8, C14 and C16. C8 was 5-methyl cytosine (mC) and remained unchanged after bisulfite treatment. The other three positions were unmethylated cytosine (C), and thus converted to uracil (U) by bisulfite treatment. Red dots under the traces mark the signature long blocks for Hg²⁺ ion binding to the U-T mismatches. Red dots in the models (left) marked the MercuLock in the DNA duplex.