Stretching DNA using the electric field in a synthetic nanopore

Jiunn B. Heng, Aleksei Aksimentiev, Chuen Ho, Patrick Marks, Yelena V. Grinkova, S Sligar, Klaus Schulten, and Gregory Timp
Nano Lett 5(10) 1883-8 (2005)
DOI:10.1021/nl0510816  PMID:16218703  BibTex

The mechanical properties of DNA over segments comparable to the size of a protein-binding site (3-10 nm) are examined using an electric-field-induced translocation of single molecules through a nanometer diameter pore. DNA, immersed in an electrolyte, is forced through synthetic pores ranging from 0.5 to 1.5 nm in radius in a 10 nm thick Si(3)N(4) membrane using an electric field. To account for the stretching and bending, we use molecular dynamics to simulate the translocation. We have found a threshold for translocation that depends on both the dimensions of the pore and the applied transmembrane bias. The voltage threshold coincides with the stretching transition that occurs in double-stranded DNA near 60 pN.