Molecular interactions in rotavirus assembly and uncoating seen by high-resolution cryo-EM
- James Z. Chena,b,1,
- Ethan C. Settembrec,1,2,
- Scott T. Aokic,
- Xing Zhanga,3,
- A. Richard Bellamyd,
- Philip R. Dormitzerc,2,
- Stephen C. Harrisonb,c,4 and
- Nikolaus Grigorieffa,b,4
- aRosenstiel Basic Medical Research Center, Brandeis University, 415 South Street, Waltham, MA 02454;
- bHoward Hughes Medical Institute,
- cLaboratory of Molecular Medicine, Children's Hospital Boston, 320 Longwood Avenue, Boston, MA 02115; and
- dSchool of Biological Sciences, University of Auckland, Auckland 1142, New Zealand
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Contributed by Stephen C. Harrison, April 11, 2009
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↵1J.Z.C. and E.C.S. contributed equally to this work. (received for review March 19, 2009)
Abstract
Rotaviruses, major causes of childhood gastroenteritis, are nonenveloped, icosahedral particles with double-strand RNA genomes. By the use of electron cryomicroscopy and single-particle reconstruction, we have visualized a rotavirus particle comprising the inner capsid coated with the trimeric outer-layer protein, VP7, at a resolution (4 Å) comparable with that of X-ray crystallography. We have traced the VP7 polypeptide chain, including parts not seen in its X-ray crystal structure. The 3 well-ordered, 30-residue, N-terminal “arms” of each VP7 trimer grip the underlying trimer of VP6, an inner-capsid protein. Structural differences between free and particle-bound VP7 and between free and VP7-coated inner capsids may regulate mRNA transcription and release. The Ca2+-stabilized VP7 intratrimer contact region, which presents important neutralizing epitopes, is unaltered upon capsid binding.
Footnotes
- 4To whom correspondence may be addressed. E-mail: harrison{at}crystal.harvard.edu or niko{at}brandeis.edu
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Author contributions: J.Z.C., E.C.S., P.R.D., S.C.H., and N.G. designed research; J.Z.C., E.C.S., S.T.A., X.Z., A.R.B., and N.G. performed research; J.Z.C., E.C.S., S.T.A., S.C.H., and N.G. analyzed data; and J.Z.C., E.C.S., P.R.D., S.C.H., and N.G. wrote the paper.
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↵2Present address: Novartis Vaccines and Diagnostics, Inc., 350 Massachusetts Avenue, Cambridge, MA 02139.
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↵3Present address: Department of Microbiology, Immunology and Molecular Genetics and the California NanoSystems Institute, University of California, Los Angeles, CA 90095-1594.
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Conflict of interest statement: E.C.S. and P.R.D. are employees and shareholders of Novartis Vaccines and Diagnostics, Inc.
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Data deposition: Density maps of 7RP and the nonicosahedrally averaged VP6–VP7 complex structure have been deposited in the Macromolecular Structure Database at the European Bioinformatics Institute (accession codes EMD-1517 and EMD-1609, respectively). The atomic structure of the 7RP capsid has been deposited in the Protein Data Bank, www.pdb.org, as 2 separate entries, VP2–VP6 (PDB ID code 3GZU) and VP7 (PDB ID code 3GZT).
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See Commentary on page 10398.
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This article contains supporting information online at www.pnas.org/cgi/content/full/0904024106/DCSupplemental.
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Freely available online through the PNAS open access option.
