 |
|
Title
|
|
Real space refinement of acto-myosin structures from sectioned muscle.
|
|
|
Authors
|
|
L.F.Chen,
E.Blanc,
M.S.Chapman,
K.A.Taylor.
|
|
|
Ref.
|
|
J Struct Biol, 2001,
133,
221-232.
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
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.
|
|
|
|