Relevance of the Drag Force during Controlled Translocation of a DNA-Protein Complex through a Glass Nanocapillary.
نویسندگان
چکیده
Combination of glass nanocapillaries with optical tweezers allowed us to detect DNA-protein complexes in physiological conditions. In this system, a protein bound to DNA is characterized by a simultaneous change of the force and ionic current signals from the level observed for the bare DNA. Controlled displacement of the protein away from the nanocapillary opening revealed decay in the values of the force and ionic current. Negatively charged proteins EcoRI, RecA, and RNA polymerase formed complexes with DNA that experienced electrophoretic force lower than the bare DNA inside nanocapillaries. Force profiles obtained for DNA-RecA in our system were different than those in the system with nanopores in membranes and optical tweezers. We suggest that such behavior is due to the dominant impact of the drag force comparing to the electrostatic force acting on a DNA-protein complex inside nanocapillaries. We explained our results using a stochastic model taking into account the conical shape of glass nanocapillaries.
منابع مشابه
Supporting Information: Relevance of the drag force during controlled translocation of a DNA-protein complex through a glass nanocapillary
Quartz capillaries with a 0.3 mm inner diameter and a 0.4 mm outer diameter were purchased from Hilgenberg. They were pulled using the program HEAT = 620, FIL = 0, VEL = 30, DEL = 140, PUL = 150 on a laser-assisted pipette puller (P-2000, Sutter Instruments). A typical pulling time was 0.30 ± 0.03 sec and diameters of the pulled capillaries were in the range of 150−200 nm. All pulled capillarie...
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عنوان ژورنال:
- Nano letters
دوره 15 10 شماره
صفحات -
تاریخ انتشار 2015