Abstract
The method presented here refines molecular conformations directly against projections of single particles measured by electron microscopy. By optimizing the orientation of the projection at the same time as the conformation, the method is well-suited to two-dimensional class averages from cryoelectron microscopy. Such direct use of two-dimensional images circumvents the need for a three-dimensional density map, which may be difficult to reconstruct from projections due to structural heterogeneity or preferred orientations of the sample on the grid. Our refinement protocol exploits Natural Move Monte Carlo to model a macromolecule as a small number of segments connected by flexible loops, on multiple scales. After tests on artificial data from lysozyme, we applied the method to the Methonococcus maripaludis chaperonin . We successfully refined its conformation from a closed-state initial model to an open-state final model using just one class-averaged projection. We also used Natural Moves to iteratively refine against heterogeneous projection images of Methonococcus maripaludis chaperonin in a mix of open and closed states. Our results suggest a general method for electron microscopy refinement specially suited to macromolecules with significant conformational flexibility. The algorithm is available in the program Methodologies for Optimization and Sampling In Computational Studies.
References
38
Referenced
32
10.1038/nature06665
10.1016/j.str.2008.02.007
10.1038/nature06893
10.1038/nature08701
10.1016/j.cell.2010.03.041
10.1073/pnas.0711623105
10.1016/j.str.2006.09.010
10.1038/nmeth992
10.1016/j.jsb.2006.01.003
10.1016/j.jmb.2008.06.021
10.1016/j.str.2004.01.015
10.1006/jmbi.1997.1611
10.1016/j.str.2007.11.016
10.1016/j.jmb.2009.07.008
10.1016/j.str.2007.09.021
10.1016/j.jsb.2004.03.002
10.1529/biophysj.104.050716
10.1016/j.str.2008.03.005
10.1038/emboj.2011.366
10.1016/j.jsb.2007.11.007
10.1002/(SICI)1097-0134(199709)29:1<1::AID-PROT1>3.0.CO;2-J
10.1021/ma60014a012
10.1021/ma00125a027
10.1063/1.479952
10.1063/1.1542611
10.1089/cmb.2010.0016
10.1042/bj20030230
10.1016/j.str.2008.01.016
10.1016/j.cell.2010.12.017
10.1038/nsmb1236
10.1016/j.str.2011.03.005
10.1006/jsbi.1999.4174
10.1007/978-0-387-68372-0_4
10.1016/j.jmb.2007.10.087
10.1073/pnas.0611593104
10.1016/j.jsb.2012.01.004
- P Minary Methodologies for Optimization and Sampling In Computational Studies (MOSAICS) version EM.3.8. http://csb.stanford.edu/~minary/MOSAICS.html. (2007).
10.1002/jcc.20084
Dates
Type | When |
---|---|
Created | 13 years, 2 months ago (June 5, 2012, 10:05 a.m.) |
Deposited | 3 years, 4 months ago (April 15, 2022, 2:44 a.m.) |
Indexed | 1 year, 3 months ago (May 9, 2024, 12:38 a.m.) |
Issued | 13 years, 2 months ago (June 4, 2012) |
Published | 13 years, 2 months ago (June 4, 2012) |
Published Online | 13 years, 2 months ago (June 4, 2012) |
Published Print | 13 years, 2 months ago (June 19, 2012) |
@article{Zhang_2012, title={Multiscale natural moves refine macromolecules using single-particle electron microscopy projection images}, volume={109}, ISSN={1091-6490}, url={http://dx.doi.org/10.1073/pnas.1205945109}, DOI={10.1073/pnas.1205945109}, number={25}, journal={Proceedings of the National Academy of Sciences}, publisher={Proceedings of the National Academy of Sciences}, author={Zhang, Junjie and Minary, Peter and Levitt, Michael}, year={2012}, month=jun, pages={9845–9850} }