Arginine Finger Serving as the Starter of Viral DNA Packaging Motors

Generally speaking, in a car engine, the starter is the part to initiate the motor operation. Biological motors are nanoscale machines ubiquitous in many biological processes in both prokaryotes and eukaryotes, [1–3] such as cell mitosis, DNA replication, [4,5] RNA transcription, [6] macromolecule trafficking, [7] and viral genome packaging [8–14]. However, the module that initiates the ATPase action has not been clearly confirmed. Identification of the starter is of great significance for assembling artificial biological motors and for elucidating their operating mechanisms.