Packaging Double-Helical DNA into Viral Capsids: Structures, Forces and Energetics
Anton S. Petrov 1 and Stephen C. Harvey 1*
1 Georgia Institute of Technology
* To whom correspondence should be addressed. E-mail: steve.harvey{at}biology.gatech.edu.
Submitted on April 19, 2008
Revised on April 22, 2008
Accepted on 22 April 2008
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Abstract |
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Small, icosahedral double-stranded DNA bacteriophage pack their genomes tightly into pre-formed protein capsids using an ATP-driven motor. Coarse-grain molecular mechanics models provide a detailed picture of DNA packaging in bacteriophage, revealing how conformation depends on capsid size, shape, and the presence or absence of a protein core. The forces that oppose packaging have large contributions from both electrostatic repulsions and from the entropic penalty of confining the DNA into the capsid, while elastic deformations make only a modest contribution. The elastic deformation energy is very sensitive to the final conformation, while the electrostatic and entropic penalties are not, so the packaged DNA favors conformations that minimize the bending energy.
Key Words:
DNA conformation, DNA energetics, bacteriophage, viral packaging
