We are pleased to announce the 2010 Cryo-EM Modeling challenge and a PSB 2011
workshop, organized by Steven Ludtke, Wah Chiu, Helen Berman and Gerard
Kleywegt.
http://ncmi.bcm.edu/challenge
* Modeling as a tool for interpretation of cryo-EM reconstructions *
Cryo-EM single particle analysis is a method for determining structures of
large molecules and macromolecular assemblies at resolutions ranging from 3.5
- 30 A. Interpreting the density maps produced by this technique represents an
ongoing challenge, for which molecular modeling techniques offer some unique
solutions.
Over the last five years, cryo-EM single particle analysis has begun producing
structures at resolutions better than 5 A, with subnanometer resolutions
becoming common. At resolutions between 5 and 9 A it becomes possible to move
beyond simple rigid-body docking and alter atomistic models to reposition
helices and sheets, to better fit the cryo-EM based density maps. At 3-5 A
resolution de-novo C-alpha traces and in some cases full atomistic models can
be constructed directly from the cyro-EM density without invoking x-ray
crystallography.
We call this a challenge rather than a contest because, unlike CASP, there is
no hidden answer to be revealed. In this project, we provide publicly
available cryo-EM densities for a selected set of structures at different
resolutions, and challenge those in the modeling community to apply their
tools to extract as much information as they can from each. At the end, the
results will be evaluated by comparing the results of different groups, and
validating against any other existing knowledge about each target. We hope
this will yield new insights into these published structures, and at the very
least, it will establish the capabilities of current modeling methods, and
give the cryo-EM community some guidance as to how to proceed with maps in
various resolution ranges. For modelers it provides a new area in which to
apply/develop their techniques, and demonstrating your tools' capabilities may
lead to new opportunities for collaboration.
Please see the challenge website for more details.
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