Retrovirus envelope protein complex structure in situ studied by cryo-electron tomography

Friedrich Förster, Ohad Medalia, Nathan Zauberman, Wolfgang Baumeister, Deborah Fass

Research output: Contribution to journalArticlepeer-review

246 Scopus citations


We used cryo-electron tomography in conjunction with single-particle averaging techniques to study the structures of frozen-hydrated envelope glycoprotein (Env) complexes on intact Moloney murine leukemia retrovirus particles. Cryo-electron tomography allows 3D imaging of viruses in toto at a resolution sufficient to locate individual macromolecules, and local averaging of abundant complexes substantially improves the resolution. The averaging of repetitive features in electron tomograms is hampered by a low signal-to-noise ratio and anisotropic resolution, which results from the "missing- wedge" effect. We developed an iterative 3D averaging algorithm that compensates for this effect and used it to determine the trimeric structure of Env to a resolution of 2.7 nm, at which individual domains can be resolved. Strikingly, the 3D reconstruction is shaped like a tripod in which the trimer penetrates the membrane at three distinct locations ≃4.5 nm apart from one another. The Env reconstruction allows tentative docking of the x-ray crystal structure of the receptor-binding domain. This study thus provides 3D structural information regarding the prefusion conformation of an intact unstained retrovirus surface protein.

Original languageEnglish
Pages (from-to)4729-4734
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number13
StatePublished - 29 Mar 2005
Externally publishedYes


  • Cryo-electron microscopy
  • Moloney murine leukemia virus
  • Single-particle analysis

ASJC Scopus subject areas

  • General


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