ELECTRON MICROSCOPY

Sample

active ribosome-nascent chain-SecYEG complex

Specimen Preperation
Sample Aggregation State PARTICLE
Vitrification Instrument FEI VITROBOT MARK III
Cryogen Name ETHANE
Sample Vitrification Details Blot 1-2 seconds before plunging into liquid ethane (FEI VITROBOT MARK III).
3D Reconstruction
Reconstruction Method SINGLE PARTICLE
Number of Particles 53000
Reported Resolution (Å) 10.1
Resolution Method FSC 0.5 CUT-OFF
Other Details The structure was solved twice: first with a model starting from a 25-Angstrom filtered E. coli ribosome map generated in house, and then a second time using a filtered ribosome model (EMD-5036). In each case, after convergence, maps from two EMAN2 refinements with different parameters were averaged after alignment in Chimera. Four maps in total were averaged to reduce the noise. Resolution method was FSC at 0.5 cut-off for a comparison between the full experimental 3D density map and a calculated map of the docked E. coli ribosome model (this map was calculated to 7 Angstrom resolution with EMAN).
Refinement Type
Symmetry Type POINT
Map-Model Fitting and Refinement
ID 1
Refinement Space REAL
Refinement Protocol FLEXIBLE FIT
Refinement Target ?
Overall B Value ?
Fitting Procedure ?
Details REFINEMENT PROTOCOL--FLEXIBLE
Data Acquisition
Detector Type KODAK SO-163 FILM
Electron Dose (electrons/Å2) 20
Imaging Experiment
Date of Experiment 2012-02-10
Temprature (Kelvin)
Microscope Model FEI TECNAI F20
Minimum Defocus (nm) 1000
Maximum Defocus (nm) 3000
Minimum Tilt Angle (degrees) ?
Maximum Tilt Angle (degrees) ?
Nominal CS 2.0
Imaging Mode BRIGHT FIELD
Specimen Holder Model OTHER
Nominal Magnification 42000
Calibrated Magnification ?
Source FIELD EMISSION GUN
Acceleration Voltage (kV) 160
Imaging Details Low dose imaging: automated single particle data collection program from TVIPS was used.
Imaging Experiment
Task Software Package Version
MODEL FITTING MDFF ?
MODEL FITTING UCSF Chimera ?
RECONSTRUCTION EMAN 2
Image Processing
CTF Correction Type CTF Correction Details Number of Particles Selected Particle Selection Details
. per micrograph