Unidirectional Translocation of DNA Through the Phi29 Connector Channel

Abstract

Nanobiomedical Center, College of Engineering and College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA. When channel diameter is reduced to the nm range (<10 nm), the interaction between the solution and channel wall starts to dominate ionic flow. An interesting phenomenon, ion current rectification, has thus been well studied, which has found its application in logic gates and diodes in fluidic circuits. Similar to the ion current rectification, we have found DNA transport through the connector channel experienced a one-way traffic mechanism. Using NTA-Ni Nanogold, we characterized the DNA transport directionality by means of single channel recording, i.e., DNA can only go through the Phi29 connector channel from the N-terminal narrow end to the C-terminal wide end. The uni-directional control in dsDNA transportation would potentially provide a novel system with a natural gate to control dsDNA loading and gene delivery in bioreactors, liposomes, and other nano-machines. The findings also forecast a ratchet or valvular mechanism of the viral DNA packaging motor.