Measurements of DNA immobilized in the alpha-hemolysin nanopore

In the past decade, there have been extensive studies aimed at exploring the potential of protein nanopores to sequence single strands of DNA using resistive pulse sensing. The high speed of DNA electrophoretically driven through these pores (∼l μs/base) necessitates high bandwidth measurements, which prevent resolution of the picoampere differences in blockage current resulting from different nucleotides. Here, we describe a procedure for the immobilization of DNA in the α-hemolysin protein nanopore which enables low-noise, high-precision measurements capable of resolving subpicoampere differences in blockage current associated with differences in the sequence and structure of the DNA.