ELECTRON MICROSCOPY
Sample
Acetylated Microtubule
Specimen Preparation
Sample Aggregation StateHELICAL ARRAY
Vitrification InstrumentFEI VITROBOT MARK IV
Cryogen NameETHANE
Sample Vitrification DetailsBlotted for 4 seconds at blot force 10.
3D Reconstruction
Reconstruction MethodHELICAL
Number of Particles18432
Reported Resolution (Å)4.1
Resolution MethodFSC 0.143 CUT-OFF
Other Details
Refinement Type
Symmetry TypeHELICAL
Axial SymmetryC1
Axial Rise9.3
Angular Rotation-27.7
Map-Model Fitting and Refinement
Id1 (3JAR)
Refinement SpaceREAL
Refinement ProtocolBACKBONE TRACE
Refinement Target0.5
Overall B Value126
Fitting Procedure
DetailsWe use PHENIX to perform real space refinement and sharpen our cryoEM maps.
Data Acquisition
Detector TypeGATAN K2 SUMMIT (4k x 4k)
Electron Dose (electrons/Å**2)25
Imaging Experiment1
Date of Experiment
Temperature (Kelvin)
Microscope ModelFEI TITAN KRIOS
Minimum Defocus (nm)1500
Maximum Defocus (nm)2500
Minimum Tilt Angle (degrees)
Maximum Tilt Angle (degrees)
Nominal CS2.7
Imaging ModeBRIGHT FIELD
Specimen Holder ModelFEI TITAN KRIOS AUTOGRID HOLDER
Nominal Magnification22500
Calibrated Magnification23364
SourceFIELD EMISSION GUN
Acceleration Voltage (kV)300
Imaging DetailsPreliminary grid screening was performed manually and all of the alignments were initially done using a gold calibration grid.
EM Software
TaskSoftware PackageVersion
PARTICLE SELECTIONAppion2.0
IMAGE ACQUISITIONSerialEM3.7
CTF CORRECTIONCTFFIND4
MODEL FITTINGPHENIX1.14
MODEL REFINEMENTPHENIX1.14
INITIAL EULER ASSIGNMENTEMAN1.9
FINAL EULER ASSIGNMENTEMAN1.9
CLASSIFICATIONEMAN1.9
RECONSTRUCTIONFREALIGN9.11
Image Processing
CTF Correction TypeCTF Correction DetailsNumber of Particles SelectedParticle Selection Details
PHASE FLIPPING AND AMPLITUDE CORRECTIONCTFFIND420256Extracted Helical Segments