Dynamics of DNA molecules in a membrane channel probed by active control techniques.
The dynamics of single-stranded DNA in an alpha-Hemolysin protein pore was studied at the single-molecule level. The escape time for DNA molecules initially drawn into the pore was measured in the absence of an externally applied electric field. These measurements revealed two well-separated timescales, one of which is surprisingly long (on the order of milliseconds). We characterized the long timescale as being associated with the binding and unbinding of DNA from the pore. We have also found that a transmembrane potential as small as 20 mV strongly biased the escape of DNA from the pore. These experiments have been made possible due to the development of a feedback control system, allowing the rapid modulation of the applied force on individual DNA molecules while inside the pore.
Bates
Mark
M
The Rowland Institute at Harvard University, Cambridge, Massachusetts 02142, USA.
Burns
Michael
M
Meller
Amit
A
D004247:DNA / Q000737:chemistry* / Q000528:radiation effects*; D004574:Electromagnetic Fields; D018274:Electroporation / Q000295:instrumentation / Q000379:methods; D005246:Feedback; D006460:Hemolysin Proteins / Q000737:chemistry*; D015640:Ion Channel Gating / Q000528:radiation effects; D007473:Ion Channels / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry* / Q000528:radiation effects; D009038:Motion; D010539:Permeability; D010812:Physical Stimulation / Q000295:instrumentation / Q000379:methods*; D016062:Porosity; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical
D006460:Hemolysin Proteins; D007473:Ion Channels; D008051:Lipid Bilayers; D004247:DNA