Document Detail


Recognition and separation of single particles with size variation by statistical analysis of their images.
MedLine Citation:
PMID:  14757057     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Macromolecules may occupy conformations with structural differences that cannot be resolved biochemically. The separation of mixed molecular populations is a pressing problem in single-particle analysis. Until recently, the task of distinguishing small structural variations was intractable, but developments in cryo-electron microscopy hardware and software now make it possible to address this problem. We have developed a general strategy for recognizing and separating structures of variable size from cryo-electron micrographs of single particles. The method uses a combination of statistical analysis and projection matching to multiple models. Identification of size variations by multivariate statistical analysis was used to do an initial separation of the data and generate starting models by angular reconstitution. Refinement was performed using alternate projection matching to models and angular reconstitution of the separated subsets. The approach has been successful at intermediate resolution, taking it within range of resolving secondary structure elements of proteins. Analysis of simulated and real data sets is used to illustrate the problems encountered and possible solutions. The strategy developed was used to resolve the structures of two forms of a small heat shock protein (Hsp26) that vary slightly in diameter and subunit packing.
Authors:
Helen E White; Helen R Saibil; Athanasios Ignatiou; Elena V Orlova
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of molecular biology     Volume:  336     ISSN:  0022-2836     ISO Abbreviation:  J. Mol. Biol.     Publication Date:  2004 Feb 
Date Detail:
Created Date:  2004-02-03     Completed Date:  2004-03-03     Revised Date:  2005-11-17    
Medline Journal Info:
Nlm Unique ID:  2985088R     Medline TA:  J Mol Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  453-60     Citation Subset:  IM    
Affiliation:
School of Crystallography, Birkbeck College, Malet Street, WC1E 7HX, London, UK.
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MeSH Terms
Descriptor/Qualifier:
Computer Simulation
Cryoelectron Microscopy / instrumentation,  methods*
Fungal Proteins / chemistry,  metabolism,  ultrastructure
Heat-Shock Proteins / chemistry*,  metabolism,  ultrastructure
Image Processing, Computer-Assisted / methods*
Models, Molecular
Multivariate Analysis
Particle Size
Protein Structure, Quaternary
Protein Structure, Secondary
Protein Subunits / chemistry,  metabolism
Software
Yeasts / chemistry
Chemical
Reg. No./Substance:
0/Fungal Proteins; 0/Heat-Shock Proteins; 0/Protein Subunits

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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