ELECTRON MICROSCOPY

Sample

Fully-loaded anthrax lethal toxin in its heptameric pre-pore state

Specimen Preperation
Sample Aggregation State PARTICLE
Vitrification Instrument GATAN CRYOPLUNGE 3
Cryogen Name ETHANE
Sample Vitrification Details 4 uL sample was applied to grid (with 2 nm additional carbon layer) and incubated for 45 s prior blotting.
3D Reconstruction
Reconstruction Method SINGLE PARTICLE
Number of Particles 210000
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 ?
Refinement Protocol FLEXIBLE FIT
Refinement Target ?
Overall B Value ?
Fitting Procedure ?
Details The protective antigen (PA) monomer from 3HVD was placed seven times into the density corresponding to the heptameric PA ring using the rigid-body fit in Chimera. Two copies of the monomeric lethal factor (LF) from 1J7N were fitted similarly into the corresponding LF density located atop of the PA7 ring. The resulting model was then flexibly fitted using iMODFIT. The model was further refined in iterative rounds of phenix and coot. Unresolved regions were deleted and side chain information was removed for less well-defined regions.
Data Acquisition
Detector Type GATAN K2 SUMMIT (4k x 4k)
Electron Dose (electrons/Å2) 74.4
Imaging Experiment
Date of Experiment ?
Temprature (Kelvin)
Microscope Model FEI TITAN KRIOS
Minimum Defocus (nm) ?
Maximum Defocus (nm) ?
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 130000
Calibrated Magnification ?
Source FIELD EMISSION GUN
Acceleration Voltage (kV) 300
Imaging Details ?
Imaging Experiment
Task Software Package Version
PARTICLE SELECTION crYOLO ?
IMAGE ACQUISITION EPU 1.10
CTF CORRECTION SPHIRE ?
MODEL FITTING iMODFIT ?
FINAL EULER ASSIGNMENT SPHIRE ?
CLASSIFICATION SPHIRE ?
RECONSTRUCTION SPHIRE ?
MODEL REFINEMENT PHENIX 1.18.2
MODEL REFINEMENT Coot 0.8.9.1
Image Processing
CTF Correction Type CTF Correction Details Number of Particles Selected Particle Selection Details
PHASE FLIPPING AND AMPLITUDE CORRECTION ?