6BIH

The Structure of the Actin-Smooth Muscle Myosin Motor Domain Complex in the Rigor State


ELECTRON MICROSCOPY
Sample
Filamentous muscle alpha-actin decorated with the motor domain of recombinant smooth muscle myosin II motor domain expressed in Sf9 cells
Sample Components
alpha-actin
myosin II
Specimen Preparation
Sample Aggregation StateFILAMENT
Vitrification InstrumentGATAN CRYOPLUNGE 3
Cryogen NameETHANE
Sample Vitrification DetailsSome specimens were frozen manually using a homemade plunger.
3D Reconstruction
Reconstruction MethodHELICAL
Number of Particles85000
Reported Resolution (Å)6
Resolution MethodFSC 0.143 CUT-OFF
Other Details
Refinement Type
Symmetry TypeHELICAL
Axial SymmetryC1
Axial Rise28.18685
Angular Rotation-166.77931
Map-Model Fitting and Refinement
Id1
Refinement SpaceREAL
Refinement ProtocolFLEXIBLE FIT
Refinement Target
Overall B Value390.86
Fitting Procedure
Details
Data Acquisition
Detector TypeDIRECT ELECTRON DE-20 (5k x 3k)
Electron Dose (electrons/Å**2)60
Imaging Experiment1
Date of Experiment
Temperature (Kelvin)
Microscope ModelFEI TITAN KRIOS
Minimum Defocus (nm)2200
Maximum Defocus (nm)5000
Minimum Tilt Angle (degrees)
Maximum Tilt Angle (degrees)
Nominal CS
Imaging ModeBRIGHT FIELD
Specimen Holder ModelFEI TITAN KRIOS AUTOGRID HOLDER
Nominal Magnification
Calibrated Magnification
SourceFIELD EMISSION GUN
Acceleration Voltage (kV)300
Imaging Details
EM Software
TaskSoftware PackageVersion
IMAGE ACQUISITIONLeginon
CTF CORRECTIONCTFFIND3.5
MODEL FITTINGRosetta
MODEL REFINEMENTRosetta
INITIAL EULER ASSIGNMENTRELION1.2
FINAL EULER ASSIGNMENTRELION1.2
CLASSIFICATIONRELION1.2
RECONSTRUCTIONRELION1.2
Image Processing
CTF Correction TypeCTF Correction DetailsNumber of Particles SelectedParticle Selection Details
PHASE FLIPPING ONLY346395Each "particle" consisted of a filament segment masked to a length of 21.0 nm, or slightly more than 7 actin subunits with 2.76 nm separation. Adjacent filament segments overlapped by about 6 subunit repeats (approximately 84% overlap).