Abstract
We find that a freely moving granular chain can be pushed, against the entropic force, into a confined cell if the passage to the cell is a channel of truncated-cone shape. In this setting, the granular chain, the cell and the channel can be considered as a mechanical analog of a DNA molecular, a bacteriophage and a portal motor, respectively. The force generated by the scaled-up analog of the mechanical motor and the packaging speed are found to be consistent with the real bacteriophage Φ29 portal motor. Pauses and slips found in single-molecule experiments of DNA packaging of the bacteriophage are also observed in the analog system. © 2011 Europhysics Letters Association.