Translocation of RecA-Coated Double-Stranded DNA through Solid-State Nanopores

We report translocation of double-stranded DNA (dsDNA) molecules that are coated with RecA protein through solid-state nanopores. Translocation measurements show current-blockade events with a wide variety in time duration (10-4-10-1 s) and conductance blockade values (3-14 nS). Large blockades (11.4+/-0.7 nS) are identified as being caused by translocations of RecA-dsDNA filaments. We confirm these results through a variety of methods, including changing molecular length and using an optical tweezer system to deliver bead-functionalized molecules to the nanopore. We further distinguish two different regimes of translocation: a low-voltage regime (<150 mV) in which the event rate increases exponentially with voltage, and a high-voltage regime in which it remains constant. Our results open possibilities for a variety of future experiments with (partly) protein-coated DNA molecules, which is interesting for both fundamental science and genomic screening applications.