[X-plor] Announcement: 2010 Cryo-EM Modelling Challenge and 2011 PSB Workshop

Gerard DVD Kleywegt via x-plor%40net.bio.net (by gerard from xray.bmc.uu.se)
Thu Jul 15 07:25:35 EST 2010


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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