7USF

ELECTRON MICROSCOPY

Sample

MMTV strand transfer complex intasome

Specimen Preperation
Sample Aggregation State PARTICLE
Vitrification Instrument HOMEMADE PLUNGER
Cryogen Name ETHANE
Sample Vitrification Details Cryo-EM grids were prepared by freezing using a manual plunger in cold room at 4C
3D Reconstruction
Reconstruction Method SINGLE PARTICLE
Number of Particles 50196
Reported Resolution (Å) 3.5
Resolution Method FSC 0.143 CUT-OFF
Other Details ?
Refinement Type
Symmetry Type POINT
Map-Model Fitting and Refinement
ID 1
Refinement Space REAL
Refinement Protocol FLEXIBLE FIT
Refinement Target CC
Overall B Value ?
Fitting Procedure ?
Details Initial model building was accomplished by rigid-body fitting of the MMTV CSC structure downloaded from the Protein Data Bank (PDB ID: 3JCA) into the EM map in Chimera 1.14 by Fit in Map tool. Unmodeled protein and DNA residues were manually built in Coot 0.9.4.1 and the structure underwent a few iterative cycles of manual model re-building and real-space refinement in Phenix. Ramachandran and secondary structure restraints were applied. To model the full octameric intasome, we additionally rigid-body docked the flanking IN dimers (PDB ID: 5CZ2) into the map. The density connecting the flanking dimers and the core was evident, but broken, and therefore a model was not derived for the linker regions. The final model accounts for the complete octameric MMTV STC intasome with connections for the linker regions.
Data Acquisition
Detector Type GATAN K2 SUMMIT (4k x 4k)
Electron Dose (electrons/Å2) 67
Imaging Experiment
Date of Experiment ?
Temprature (Kelvin)
Microscope Model FEI TITAN KRIOS
Minimum Defocus (nm) 1000
Maximum Defocus (nm) 3000
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 22500
Calibrated Magnification 38167
Source FIELD EMISSION GUN
Acceleration Voltage (kV) 300
Imaging Details ?
Imaging Experiment
Task Software Package Version
IMAGE ACQUISITION Leginon ?
CTF CORRECTION cryoSPARC 3.0
MODEL FITTING PHENIX dev-4213-000
INITIAL EULER ASSIGNMENT cryoSPARC 2.4
FINAL EULER ASSIGNMENT cryoSPARC 2.4
RECONSTRUCTION cryoSPARC 3.0
MODEL REFINEMENT Coot ?
Image Processing
CTF Correction Type CTF Correction Details Number of Particles Selected Particle Selection Details
PHASE FLIPPING AND AMPLITUDE CORRECTION ?