ELECTRON MICROSCOPY


Sample

DNA polymerase III alpha, beta, epsilon, theta complex with mismatched DNA duplex

Specimen Preperation
Sample Aggregation State PARTICLE
Vitrification Instrument FEI VITROBOT MARK IV
Cryogen Name ETHANE
Sample Vitrification Details Prior to sample preparation 0.1 volumes of 0.05% Tween 20 were added to the sample 3 microliters were pipetted onto the grid and blotted for 4 seconds
3D Reconstruction
Reconstruction Method SINGLE PARTICLE
Number of Particles 15616
Reported Resolution (Å) 6.7
Resolution Method FSC 0.143 CUT-OFF
Other Details ?
Refinement Type
Symmetry Type POINT
Map-Model Fitting and Refinement
ID 1
Refinement Space ?
Refinement Protocol OTHER
Refinement Target ?
Overall B Value ?
Fitting Procedure ?
Details The cryo-EM structure of the PolIIIalpha-clamp-exonuclease complex in the polymerase mode (PDB code: 5FKW) was used as a starting model, and the NMR structure of theta bound to the exonuclease catalytic domain (PDB code: 2XY8) was used to place theta into the cryo-EM map. The model was manually adjusted in Coot and geometry of the protein optimized in Refmac5 using DNA-specific restraints generated in LibG
Data Acquisition
Detector Type GATAN K2 SUMMIT (4k x 4k)
Electron Dose (electrons/Å2) 2
Imaging Experiment
Date of Experiment ?
Temprature (Kelvin)
Microscope Model FEI TITAN KRIOS
Minimum Defocus (nm) 1800
Maximum Defocus (nm) 3500
Minimum Tilt Angle (degrees) ?
Maximum Tilt Angle (degrees) ?
Nominal CS 2.7
Imaging Mode BRIGHT FIELD
Specimen Holder Model FEI TITAN KRIOS AUTOGRID HOLDER
Nominal Magnification 64000
Calibrated Magnification 79545
Source FIELD EMISSION GUN
Acceleration Voltage (kV) 300
Imaging Details ?
Imaging Experiment
Task Software Package Version
PARTICLE SELECTION RELION 2
IMAGE ACQUISITION DigitalMicrograph 2.3
IMAGE ACQUISITION Titan User Interface ?
CTF CORRECTION Gctf ?
MODEL FITTING Coot 0.8.2
INITIAL EULER ASSIGNMENT RELION 2
FINAL EULER ASSIGNMENT RELION 2
CLASSIFICATION RELION 2
RECONSTRUCTION RELION 2
MODEL REFINEMENT REFMAC 5.8
MODEL REFINEMENT LIBG ?
Image Processing
CTF Correction Type CTF Correction Details Number of Particles Selected Particle Selection Details
NONE ?