3J4S

Helical Model of TubZ-Bt four-stranded filament

ELECTRON MICROSCOPY

Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
experimental model	PDB	2XKA
experimental model	PDB	2XKB

Sample
TubZ-Bt

Specimen Preparation
Sample Aggregation State	FILAMENT
Vitrification Instrument	FEI VITROBOT MARK III
Cryogen Name	ETHANE
Sample Vitrification Details	Add GTP to grow filaments for 6 minutes before application to grid. Blot 4.5 seconds before plunging into liquid ethane (FEI VITROBOT MARK III).

3D Reconstruction
Reconstruction Method	HELICAL
Number of Particles
Reported Resolution (Å)	6.8
Resolution Method	FSC 0.143 CUT-OFF
Other Details	Final map has been low-pass filtered to 7 Angstrom and high-pass filtered to 30 Angstrom. A B-factor of -309 Angstrom was applied using the program bf ...	Final map has been low-pass filtered to 7 Angstrom and high-pass filtered to 30 Angstrom. A B-factor of -309 Angstrom was applied using the program bfactor. A cylindrical mask of radius ~80 Angstrom has been applied.
Refinement Type
Symmetry Type	HELICAL
Axial Symmetry	C4
Axial Rise	43.54512
Angular Rotation	31.78843

Map-Model Fitting and Refinement
Id	1 (2XKA, 2XKB)
Refinement Space	REAL
Refinement Protocol
Refinement Target
Overall B Value
Fitting Procedure
Details	DETAILS--Initial local fitting was done using Chimera and then Molecular Dynamics Flexible Fitting (MDFF) was used for flexible fitting.

Data Acquisition
Detector Type	TVIPS TEMCAM-F816 (8k x 8k)
Electron Dose (electrons/Å**2)	20

Imaging Experiment	1
Date of Experiment	2011-04-22
Temperature (Kelvin)
Microscope Model	FEI TECNAI F20
Minimum Defocus (nm)	800
Maximum Defocus (nm)	3500
Minimum Tilt Angle (degrees)
Maximum Tilt Angle (degrees)
Nominal CS	2.2
Imaging Mode	BRIGHT FIELD
Specimen Holder Model	OTHER
Nominal Magnification	62000
Calibrated Magnification
Source	FIELD EMISSION GUN
Acceleration Voltage (kV)	200
Imaging Details

EM Software
Task	Software Package	Version
MODEL FITTING	MDFF
RECONSTRUCTION	SPIDER

Image Processing
CTF Correction Type	CTF Correction Details	Number of Particles Selected	Particle Selection Details
	Whole Micrograph

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729.