Figure 4. Representative single-channel electrical trace showing the NCp7-SL3 RNA aptamer interactions using a large nanopore.

(A) The addition of 1 μM NCp7 protein increases the frequency of large amplitude current blockades observed with a large-diameter (~7nm) nanopore in a thick (~30 nm) silicon nitride membrane when added to a solution containing 1 μM high-affinity SL3 (GAG) aptamer; (B) A scatter plot of current amplitude versus dwell time showing distinct event types. Low-amplitude current blockades are attributed to the SL3 RNA aptamer alone. Large-amplitude events are interpreted as current blockades produced by the NCp7-SL3 RNA aptamer complex. Square events represent measurements taken with SL3 (GAG) solution in the chamber, while circle events indicate data taken with both SL3 (GAG) and NCp7 added to the chamber. The applied transmembrane potential was +200 mV. The buffer solution contained 200 mM NaCl, 5mM NaH₂PO₄, pH 7.0 on the cis side, and 1 M NaCl, 5 mM NaH₂PO₄, pH 7.0 on the trans side.