Detailed kinetic analysis of the φ29 DNA packaging motor providing evidence for coordinated intersubunit ATPase activity of gp16

Presented is a detailed kinetic evaluation of the motor component interactions of the DNA translocation ATPase of Bacillus subtilis bacteriophage φ29. The components of the φ29 DNA packaging motor, comprised of both protein and non-protein parts, act in a coordinated manner to translocate DNA into a viral capsid, despite entropically unfavorable conditions. The precise nature of this coordination remains under investigation but recent results have shown that the gp16 pentamer acts to propel the genomic DNA in 10 base pair bursts, implying inter-subunit synchronization. We observe an emergent tandem coordination behavior in the ATPase activity of gp16 as demonstrated by a Hill coefficient of 2.4±0.2, as differentiated from its activity in DNA packaging which has been shown to have a unity Hill coefficient. Due to its relative strength and DNA packaging efficiency, understanding the molecular mechanism of force generation may prove useful to various nanotechnology applications including gene therapy, control of biological ATPases, and the powering of nanoscale mechanical devices.

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