EM Sample
Sample Concentration (mg/ml) 0.15
Sample pH 7.5
Sample Vitrification Details holey carbon grid at 20C; flash frozen into liquid ethan
Sample Aggregation State PARTICLE
Name of Sample release factor RF2 bound to E. coli ribosomes
Sample Details E. coli ribosomes, paused with a UAA stop codon in the A site and a tetrapeptidyl-tRNA in the P site, added release factor RF2
EM Data Acquisition
Date of Experiment 2001-09-06
Num of Micrographs-Images Used 78
Temperature (Kelvin) 100.0
Microscope Model FEI/PHILIPS CM200FEG/ST
Detector Type KODAK SO163 FILM
Minimum Defocus (nm) 500.0
Maximum Defocus (nm) 2900.0
Minimum Tilt Angle (degrees) 0.0
Maximum Tilt Angle (degrees) 0.0
Nominal CS 2.1
Electron Dose (electrons nm**-2) 1000.0
Illumination Mode FLOOD BEAM
Nominal Magnification 50000
Calibrated Magnification 48000
Acceleration Voltage (kV) 200
Imaging Details low dose mode
3D Reconstruction
Software Package(s)
Reconstruction Method angular reconstitution, exact filtered back-projection
EM Image Reconstruction Statistics
Number of Particles 15800
Nominal Pixel Size 2.419
Actual Pixel Size 2.419
Effective Resolution 14.0
CTF Correction Method phase flipping CTF correction of each particle as function of position in the micrograph
EM Reconstruction Magnification Callibration scaling with respect to 70S crystal structure (PDB codes 1GIX and 1GIY)
Other Details iterative refinement procedure as described in Quat. Rev. of Biophysics 33, 4 (2000), pp. 307-369
EM Map-Model Fitting and Refinement
Refinement Space Refinement Protocol Refinement Target Overall B Value Fitting Procedure Fitting Software
REAL rigid body fit of the 70S ribosome without individual fitting of proteins or RNA fragments. Rigid body fit of three individual domains of release factor RF2 keeping the connectivity; linkers betweenn domains defined based on temperature factors of crystal structure, conserved Gly and Pro residues, proteolytic sites, and global domain architecture best visual fit using the program O -- -- --