A 11.5 Å single particle reconstruction of GroEL using EMAN

Steven J. Ludtke, Joanita Jakana, Jiu Li Song, David T. Chuang, Wah Chiu

Research output: Contribution to journalArticlepeer-review

116 Scopus citations


Single-particle analysis has become an increasingly important method for structural determination of large macromolecular assemblies. GroEL is an 800 kDa molecular chaperone, which, along with its co-chaperonin GroES, promotes protein folding both in vitro and in the bacterial cell. EMAN is a single-particle analysis software package, which was first publicly distributed in 2000. We present a three-dimensional reconstruction of native naked GroEL to ∼11.5 Å performed entirely with EMAN. We demonstrate that the single-particle reconstruction, X-ray scattering data and X-ray crystal structure all agree well at this resolution. These results validate the specific methods of image restoration, reconstruction and evaluation techniques implemented in EMAN. It also demonstrates that the single-particle reconstruction technique and X-ray crystallography will yield consistent structure factors, even at low resolution, when image restoration is performed correctly. A detailed comparison of the single-particle and X-ray structures exhibits some small variations in the equatorial domain of the molecule, likely due to the absence of crystal packing forces in the single-particle reconstruction.

Original languageEnglish (US)
Pages (from-to)253-262
Number of pages10
JournalJournal of Molecular Biology
Issue number2
StatePublished - Nov 23 2001


  • Electron cryomicroscopy
  • GroEL
  • Single-particle reconstruction
  • Structure
  • X-ray scattering

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology


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