Discovery of a new motion mechanism of biomotors similar to the earth revolving around the sun without rotation

- New motion mechanism of revolution without rotation found for phi29 DNA packaging.
- Revolution motor finding expands classical linear and rotation biomotor classes.
- Revolution motors transport dsDNA unidirectionally without supercoiling.
- New mechanism solves many puzzles, mysteries, and debates in biomotor studies.
- Motors with all numbers of subunits can utilize the revolution mechanism.

Biomotors have been classified into linear and rotational motors. For 35 years, it has been popularly believed that viral dsDNA-packaging apparatuses are pentameric rotation motors. Recently, a third class of hexameric motor has been found in bacteriophage phi29 that utilizes a mechanism of revolution without rotation, friction, coiling, or torque. This review addresses how packaging motors control dsDNA one-way traffic; how four electropositive layers in the channel interact with the electronegative phosphate backbone to generate four steps in translocating one dsDNA helix; how motors resolve the mismatch between 10.5 bases and 12 connector subunits per cycle of revolution; and how ATP regulates sequential action of motor ATPase. Since motors with all number of subunits can utilize the revolution mechanism, this finding helps resolve puzzles and debates concerning the oligomeric nature of packaging motors in many phage systems. This revolution mechanism helps to solve the undesirable dsDNA supercoiling issue involved in rotation.