Real space refinement of acto-myosin structures from sectioned muscle

Li Fan Chen, Eric Blanc, Michael S. Chapman, Kenneth A. Taylor

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


We have adapted a real space refinement protocol originally developed for high-resolution crystallographic analysis for use in fitting atomic models of actin filaments and myosin subfragment 1 (S1) to 3-D images of thin-sectioned, plastic-embedded whole muscle. The rationale for this effort is to obtain a refinement protocol that will optimize the fit of the model to the density obtained by electron microscopy and correct for poor geometry introduced during the manual fitting of a high-resolution atomic model into a lower resolution 3-D image. The starting atomic model consisted of a rigor acto-S1 model obtained by X-ray crystallography and helical reconstruction of electron micrographs. This model was rebuilt to fit 3-D images of rigor insect flight muscle at a resolution of 7 nm obtained by electron tomography and image averaging. Our highly constrained real space refinement resulted in modest improvements in the agreement of model and reconstruction but reduced the number of conflicting atomic contacts by 70% without loss of fit to the 3-D density. The methodology seems to be well suited to the derivation of stereochemically reasonable atomic models that are consistent with experimentally determined 3-D reconstructions computed from electron micrographs.

Original languageEnglish (US)
Pages (from-to)221-232
Number of pages12
JournalJournal of Structural Biology
Issue number2-3
StatePublished - 2001
Externally publishedYes


  • Electron microscopy
  • Insect flight muscle
  • Tomography

ASJC Scopus subject areas

  • Structural Biology


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