Enhanced translocation of single DNA molecules through α-hemolysin nanopores by manipulation of internal charge

• Published in: Proceedings of the National Academy of Sciences - PNAS 2008-12, Vol.105 (50), p.19720-19725
• Main Authors: Maglia, Giovanni, Restrepo, Marcela Rincon, Mikhailova, Ellina, Bayley, Hagan
• Format: Article
• Language: English
• Subjects: Amino acids; Anions; Bacterial Toxins - chemistry; Bacterial Toxins - genetics; Biological Sciences; Biological Transport; Cations; DNA; DNA, Single-Stranded - chemistry; Electric current; Electric potential; Genetic Engineering; Hemolysin Proteins - chemistry; Hemolysin Proteins - genetics; Molecules; Nanostructures - chemistry; Nanotechnology; Nucleic acids; Point Mutation; Porosity; Protein Folding; Sequencing; Surface Properties
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0808296105

Both protein and solid-state nanopores are under intense investigation for the analysis of nucleic acids. A crucial advantage of protein nanopores is that site-directed mutagenesis permits precise tuning of their properties. Here, by augmenting the internal positive charge within the α-hemolysin pore and varying its distribution, we increase the frequency of translocation of a 92-nt single-stranded DNA through the pore at +120 mV by [almost equal to]10-fold over the wild-type protein and dramatically lower the voltage threshold at which translocation occurs, e.g., by 50 mV for 1 event·s⁻¹·μM⁻¹. Further, events in which DNA enters the pore, but is not immediately translocated, are almost eliminated. These experiments provide a basis for improved nucleic acid analysis with protein nanopores, which might be translated to solid-state nanopores by using chemical surface modification.