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Dynamics of herpes simplex virus capsid maturation visualized by time-lapse cryo-electron microscopy

Nature Structural Biology volume 10, pages 334341 (2003) | Download Citation

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Abstract

The capsid of the herpes simplex virus initially assembles as a procapsid that matures through a massive conformational change of its 182 MDa surface shell. This transition, which stabilizes the fragile procapsid, is facilitated by the viral protease that releases the interaction between the shell and the underlying scaffold; however, protease-deficient procapsids mature slowly in vitro. To study procapsid maturation as a time-resolved process, we monitored this reaction by cryo-electron microscopy (cryo-EM). The resulting images were sorted into 17 distinct classes, and three-dimensional density maps were calculated for each. When arranged in a chronological series, these maps yielded molecular movies of procapsid maturation. A single major switching event takes place at stages 8–9, preceded by relatively subtle adjustments in the pattern of interactions and followed by similarly small 'aftershocks'. The primary mechanism underlying maturation is relative rotations of domains of VP5, the major capsid protein.

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Acknowledgements

We thank D. Belnap for programming contributions. This project was supported in part by the NIH Targeted Antiviral Program (A.C.S.). J.C.B. acknowledges grant support from the NIH and the NSF.

Author information

Affiliations

  1. Laboratory of Structural Biology, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland 20892.

    • J. Bernard Heymann
    • , Naiqian Cheng
    • , Benes L. Trus
    •  & Alasdair C. Steven
  2. Department of Microbiology, University of Virginia Health System, Charlottesville, Virginia 22908.

    • William W. Newcomb
    •  & Jay C. Brown
  3. Imaging Sciences Laboratory, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892.

    • Benes L. Trus

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Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Alasdair C. Steven.

Supplementary information

Videos

  1. 1.

    Supplementary Video 1

    During the maturation process, the herpes simplex virus 1 precursor particle (procapsid) progresses through a succession of states from the naïve procapsid (state 1) to the fully mature capsid (state 17). The states were captured by cryo-EM and image reconstruction and are displayed here as time-lapse videos. The number (upper left) refers to the state. The particle is a T = 16 icosahedron, 1,250 Å in diameter.Video 1 shows the changes in the outer surface.

  2. 2.

    Supplementary Video 2

    Video 2 shows the changes in the inner surface of the capsid viewed along a two-fold axis of symmetry.

  3. 3.

    Supplementary Video 3

    Video 3 is a close-up view of a portion of the inner surface.

  4. 4.

    Supplementary Video 4

    Video 4 is a close-up view of a portion the outer surface, centered on a peripentonal hexon (P-hexon). To its left is a penton, and to its right, an E-hexon (edge hexon).

  5. 5.

    Supplementary Video 5

    Video 5 shows a cutaway view through part of the surface shell, which is 150 Å thick. It sections through hexons and pentons of the major capsid protein and through the triplex complexes located at local three-fold symmetry axes. The inner scaffolding shell is not shown.

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DOI

https://doi.org/10.1038/nsb922

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