Construction of Asymmetrical Hexameric Biomimetic Motors with Continuous Single-Directional Motion by Sequential Coordination

Abstract

The significance of bionanomotors in nanotechnology is analogous to mechanical motors in daily life. Here we report the principle and approach for designing and constructing biomimetic nanomotors with continuous single-directional motion. This bionanomotor is composed of a dodecameric protein channel, a six-pRNA ring, and an ATPase hexamer. Based on recent elucidations of the one-way revolving mechanisms of phi29 dsDNA motor, various RNA and protein elements was designed and tested by single-molecule imaging and biochemical assays, with that, we have constructed the motor with active components. The motor motion direction was controlled by three operation elements: 1. Asymmetrical ATPase with ATP-interacting domains for alternative DNA binding/pushing regulated by an arginine finger in a sequential action manner. The arginine finger bridges two adjacent ATPase subunits into a non-covalent dimer, resulting in an asymmetrical hexameric complex containing one dimer and four monomers. 2. The dsDNA translocation channel as a one-way valve. 3. The hexameric pRNA ring geared with left-/right-hand loops. Assessments of these constructs revealed that one inactive subunit of pRNA/ATPase is sufficient to completely block the motor function (defined as K = 1), implying that these components worked sequentially based on the principle of binomial distribution and Yang Hui’s Triangle.

Controlling the Revolving and Rotating Motion Direction of Asymmetric Hexameric Nanomotor by Arginine Finger and Channel Chirality

“…Most commonly studied mutations are substitutions of glutamate and aspartate by glutamine or alanine. 56,110,125,131,132 Upon these mutations, ATP hydrolysis is prevented, but ATP binding is retained.…”

“…33,133 Mutations of the sensor 2 residues led to a loss or decrease of ATP binding and/or ATP hydrolysis. 110,125,135−138…”

“…Mutated gp16 was found to lose the capability to incorporate into the hexameric ring, to bind dsDNA, or to package DNA. 110,125…”

“…Substitution mutations that replace the arginine residue with neutral residues result in the loss of ATPase function. 29,110,125…”

“…Some reports suggest that the arginine finger is a cis -acting component that functions within a single subunit of the ATPase ring, 43 while others report that the arginine finger is a trans -acting factor that bridges two adjacent subunits. 29,110,125,159,162−164 Some studies even suggest that there are two arginine fingers in each ATPase subunit. 109,139 It has also been reported that the reduction in ATPase activity upon arginine finger mutation is due to an effect on catalysis but not ATP binding.…”