Figure 1. Detection of a single T-Hg-T MercuLock in the nanopore.

The mixture of target T_T and probe P_T were presented in cis solution. (a) and (b). Representative current traces, multi-level signature blocks, block duration histograms and corresponding diagram of molecular configurations, in the absence of Hg²⁺ (a) and in the presence of Hg²⁺ (b). The sequences of T_T and P_T are shown in Table S1. Traces were recorded at +130 mV (cis grounded) in 1 M KCl buffered with 10 mM Tris (pH 7.4). cis solution contained 1 μM T_T and 1 μM P_T. In b, 10 μM HgCl₂ was presented in cis solution. Red dots under the trace in panel b mark the long block signatures for the T_T·P_T hybrid bound with a Hg²⁺ ion to the T-T mismatch. Values of block duration were given in Table S2. Red dot in the model in panel b represents the MercuLock formed in the DNA duplex.