Fig. 3.

Single nucleotide sensitivity. (a) Schematic of initial experiments with DNA held stationary in the pore by tethering it to a large streptavidin molecule. (b) These experiments showed that homopolymer strands containing each base had its own unique current. (c) Single nucleotide substitutions of nucleotides held within the pore at various positions shown in (a) such as a single C replacing an A at various positions along a homopolymer A DNA strand showed that the region of sensitivity for MspA was ~4 nucleotides wide, and that the substitution of a single base held within the constriction was detectable. (b) and (c) modified from [7].