Biomedical Engineering Reference
In-Depth Information
Chapter 4
Membrane-Embedded Channel
of Bacteriophage Phi29 DNA-Packaging
Motor for Translocation and Sensing
of Double-Stranded DNA
Farzin Haque and Peixuan Guo
Abstract Living systems contain a wide variety of nanomachines and highly-ordered
macromolecular structures with diverse functions. All linear double-stranded (ds)
DNA viruses package their genome into a pre-formed protein shell via an Adenosine-
5'-triphosphate (ATP) driven nanomotor. The novel and ingenious design of the
bacteriophage phi29 DNA packaging motor with an elegant and elaborate channel
has inspired its applications in nanotechnology. The central component of the phi29
motor is a connector composed of 12 copies of the protein gp10, which forms a
dodecamer channel acting as a path for the translocation of dsDNA, which enters
the protein shell during replication and exits into the host cell during infection. The
diameter of the channel is 3.6 nm at the narrow end and 6 nm at its wider end. The
connector has been successfully inserted into a lipid bilayer and exhibited robust
capability for extremely reliable and precise assessment of the transportation of ions
and DNA as revealed by single channel conductance assays. In addition, the bacterio-
phage phi29 DNA packaging motor exercised a one-way traffic property for dsDNA
translocation from N-terminal entrance to C-terminal exit with a valve mechanism in
DNA-packaging. These findings have important implications since artificial membrane
architecture for DNA packaging motor would allow detailed investigations into discrete
mechanisms of motor operation as well as future avenues for therapeutic dsDNA
packaging, sampling, and delivery.
Keywords Bacteriophage phi29 DNA packaging Nanomotor Connector
Liposomes Ion channel Single channel conductance Membrane channel
Viral assembly Stoichiometry quantification Nanostructure Bionanotechnology
Nanobiotechnology Nanomedicine
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