ELECTRON MICROSCOPY

Sample

Sindbis Virus

Specimen Preperation
Sample Aggregation State PARTICLE
Vitrification Instrument
Cryogen Name
Sample Vitrification Details
3D Reconstruction
Reconstruction Method SINGLE PARTICLE
Number of Particles ?
Reported Resolution (Å) 11.4
Resolution Method ?
Other Details ?
Refinement Type
Symmetry Type POINT
Map-Model Fitting and Refinement
ID 1
Refinement Space REAL
Refinement Protocol ?
Refinement Target ?
Overall B Value 1000
Fitting Procedure ?
Details DETAILS--The structure of the lipid-enveloped Sindbis virus has been determined by fitting atomic resolution crystallographic structures of component proteins into an 11 resolution cryo- electron microscopy (cryoEM) map (with significant terms to 10 resolution). The E1 glycoprotein, whose structure had been determined independently for the homologous Semliki Forest virus by X-ray crystallography (Lescar, J., Roussel,A., Wein, M.W., Navaza, J., Fuller, S.D., Wengler, G., and Rey, F.A. (2001). The fusion glycoprotein shell of Semliki Forest virus- an icosahedral assembly primed for fusogenic activation at endosomal pH. Cell 105, 137-148), was fitted into the cryoEM density, in part by using the known positions of glycoprotein sites as restraints. The well-resolved transmembrane regions form coiled coils that could be fitted with the dimeric GCN4 coiled-coil structure. The helices could be seen to extend to E1 and E2 on the outside of the membrane and to the nucleocapsid on the inside. The known structure of the capsid protein (Choi, H.K., Tong, L., Minor, W., Dumas, P., Boege, U., Rossmann, M.G., and Wengler, G. (1991). Structure of Sindbis virus core protein reveals a chymotrypsin-like serine proteinase and the organization of the virion. Nature 354, 37-43.) was fitted into the density corresponding to the nucleocapsid, revising an earlier published structure.
Data Acquisition
Detector Type KODAK SO-163 FILM
Electron Dose (electrons/Å2) 18.4
Imaging Experiment
Date of Experiment 2000-06-15
Temprature (Kelvin)
Microscope Model FEI/PHILIPS CM200T
Minimum Defocus (nm) 1100
Maximum Defocus (nm) 2580
Minimum Tilt Angle (degrees) 0
Maximum Tilt Angle (degrees) 0
Nominal CS 2.0
Imaging Mode BRIGHT FIELD
Specimen Holder Model ?
Nominal Magnification 38000
Calibrated Magnification ?
Source FIELD EMISSION GUN
Acceleration Voltage (kV) 200
Imaging Details ?
Imaging Experiment
Task Software Package Version
MODEL FITTING EMfit ?
RECONSTRUCTION EM3DR ?
Image Processing
CTF Correction Type CTF Correction Details Number of Particles Selected Particle Selection Details
. each viral image was CTF corrected before reconstruction, based on the following equation: F(corr)=F(obs)/[|CTF|+wiener]