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Jinghua Tang
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, Norman Olson
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, Paul J. Jardine
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, Shelley Grimes
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, Dwight L. Anderson
2,3,*
and
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Timothy S. Baker
1,4,*
Department of Chemistry and Biochemistry,
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Department of Molecular Biology,
University of California-San Diego, La Jolla, CA 92093
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Department of Diagnostic and Biological Sciences, Institute for Molecular Virology and
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Department of Microbiology, University of Minnesota, Minneapolis, MN 55455
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*
Corresponding authors (tsb@ucsd.edu, dlander@umn.edu).
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We present here the first asymmetric, three-dimensional reconstruction of a tailed dsDNA virus, the mature bacteriophage
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29, at sub-nanometer resolution. This structure reveals the rich detail
12 of the asymmetric interactions and conformational dynamics of the
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29 protein and DNA
13 components, and provides novel insight into the mechanics of virus assembly. For example, the
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16 dodecameric head-tail connector protein undergoes significant rearrangement upon assembly into the virion. Specific interactions occur between the tightly packed dsDNA and the proteins of the head and tail. Of particular interest and novelty, a ~60Å diameter toroid of dsDNA was
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19 observed in the connector-lower collar cavity. The extreme deformation that occurs over a small stretch of DNA is likely a consequence of the high pressure of the packaged genome. This toroid structure may help retain the DNA inside the capsid prior to its injection into the bacterial host.
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