3J68

Structural mechanism of the dynein powerstroke (pre-powerstroke state)

ELECTRON MICROSCOPY

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Sample
active sea urchin sperm flagella

Specimen Preparation
Sample Aggregation State	PARTICLE
Vitrification Instrument	HOMEMADE PLUNGER
Cryogen Name	ETHANE
Sample Vitrification Details	Blot for 1.5-2.5 seconds before plunging in liquid ethane.

3D Reconstruction
Reconstruction Method	TOMOGRAPHY
Number of Particles
Reported Resolution (Å)	30
Resolution Method	FSC 0.5 CUT-OFF
Other Details	Final maps were calculated by averaging 2800 particles from 41 tomograms. Axonemal repeats (96 nm long) from 41 tomograms (reconstructed using fiducial alignment and weighted backprojection, IMOD software, Kremer et al. 1996) were aligned and averaged using the PEET software (bio3d.colorado.edu, Nicastro et al. 2006). To obtain structures with consistent conformations, classification of the different conformational states of dynein was performed using a clustering approach implemented in PEET (Heumann et al. 2011).
Refinement Type
Symmetry Type	POINT
Point Symmetry	C1

Map-Model Fitting and Refinement
Id	1 (4AKI)
Refinement Space
Refinement Protocol	RIGID BODY FIT
Refinement Target	Cross-correlation coefficient
Overall B Value
Fitting Procedure
Details	REFINEMENT PROTOCOL--rigid body DETAILS--Initial local fitting was done using Chimera and then manual adjustment was performed.

Data Acquisition
Detector Type	GENERIC GATAN (2k x 2k)
Electron Dose (electrons/Å**2)	100

Imaging Experiment	1
Date of Experiment	2012-04-07
Temperature (Kelvin)	80
Microscope Model	FEI TECNAI F30
Minimum Defocus (nm)	6000
Maximum Defocus (nm)	8000
Minimum Tilt Angle (degrees)	-65
Maximum Tilt Angle (degrees)	65
Nominal CS
Imaging Mode	BRIGHT FIELD
Specimen Holder Model	GATAN LIQUID NITROGEN
Nominal Magnification	13500
Calibrated Magnification
Source	FIELD EMISSION GUN
Acceleration Voltage (kV)	300
Imaging Details

EM Software
Task	Software Package	Version
RECONSTRUCTION	IMOD
RECONSTRUCTION	PEET