Electrophoretic force on a protein-coated dna molecule in a solid-state nanopore

Adam R. Hall, Stijn Van Dorp, Serge G. Lemay, Cees Dekker*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

62 Citations (Scopus)


Using solid-state nanopores with optical tweezers, we perform force spectroscopy on DNA molecules that are coated with RecA proteins. We observe that the electrophoretic force is 2-4 times larger for RecA-DNA filaments than for uncoated DNA molecules and that this force increases at lower salt concentrations. The data demonstrate the efficacy of solid-state nanopores for locally probing the forces on DNAbound proteins. Our results are described quantitatively by a model that treats the electrophoretic and hydrodynamic forces. The conductance steps that occur when RecA-DNA enters the nanopore change from conductance decreases at high salt to conductance increases at low salt, which allows the apparent charge of the RecA-DNA filament to be extracted. The combination of conductance measurements with local force spectroscopy increases the potential for future solid-state nanopore screening devices.

Original languageEnglish
Pages (from-to)4441-4445
Number of pages5
JournalNano letters
Issue number12
Publication statusPublished - 9 Dec 2009
Externally publishedYes

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