Linear double-stranded DNA (dsDNA) viruses package its genome into a preformed procapsid fueled by the energy from ATP hydrolysis. The bacteriophage phi29 motor has a truncated cone shaped protein component, named connector, with a central channel of 3.6 nm at its narrowest part. The connector protein has been successfully inserted into an artificial lipid bilayer membrane, and the channel exhibited robust capability under various salt and pH conditions as revealed by single channel studies. This channel is suitable for extremely precise assessment of the transportation of small molecules, such as ions, DNA and RNA.
There is an urgent need to development a highly sensitive detection system, for the applications in the area of pathogen detection, disease diagnosis, environmental monitoring, etc. The current challenges and limitations of these technologies are the sensitivity and accuracy issues arising from background noise and nonspecific reactions. The property of phi29 motor channel has been studied at various conditions, and was incorporated into lipid membrane. The motor channel exercised a one-way traffic property during the process of dsDNA translocation with a valve mechanism. In addition, the opening and closure of the channel also exhibit reversible and controllable. A modified version of the connector channel is founded to have a smaller channel size, which is able to detect the ssDNA and ssRNA. These findings have important implications since this artificial membrane-embedded channel would allow detailed investigations into the mechanisms of viral motor operation, as well as future applications for therapeutic molecule packaging, delivery, single molecule sensing and drug screening.