Structural changes in a marine podovirus associated with release of its genome into Prochlorococcus

Nat Struct Mol Biol. 2010 Jul;17(7):830-6. doi: 10.1038/nsmb.1823. Epub 2010 Jun 13.


Podovirus P-SSP7 infects Prochlorococcus marinus, the most abundant oceanic photosynthetic microorganism. Single-particle cryo-electron microscopy yields icosahedral and asymmetrical structures of infectious P-SSP7 with 4.6-A and 9-A resolution, respectively. The asymmetric reconstruction reveals how symmetry mismatches are accommodated among five of the gene products at the portal vertex. Reconstructions of infectious and empty particles show a conformational change of the 'valve' density in the nozzle, an orientation difference in the tail fibers, a disordering of the C terminus of the portal protein and the disappearance of the core proteins. In addition, cryo-electron tomography of P-SSP7 infecting Prochlorococcus showed the same tail-fiber conformation as that in empty particles. Our observations suggest a mechanism whereby, upon binding to the host cell, the tail fibers induce a cascade of structural alterations of the portal vertex complex that triggers DNA release.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Capsid / chemistry*
  • Capsid / metabolism
  • Genome, Viral
  • Models, Molecular
  • Podoviridae / chemistry*
  • Podoviridae / genetics
  • Podoviridae / metabolism
  • Podoviridae / pathogenicity*
  • Prochlorococcus / virology*
  • Viral Proteins / chemistry*
  • Viral Proteins / metabolism
  • Virion / chemistry


  • Viral Proteins

Associated data

  • PDB/2XD8