Tarantula heavy meromyosin obtained by flexible docking to Tarantula muscle thick filament Cryo-EM 3D-MAP
ELECTRON MICROSCOPY
Sample
Myosin thick filaments from Tarantula striated muscle
Specimen Preparation
Sample Aggregation State
FILAMENT
Vitrification Instrument
Cryogen Name
Sample Vitrification Details
Plunging in a liquid ethane.
Blotting was performed from one side of the grid till a thin sample film on it using Whatman
No 42 filter paper, then ...
Plunging in a liquid ethane.
Blotting was performed from one side of the grid till a thin sample film on it using Whatman
No 42 filter paper, then the grid was immediately plunged under gravity into liquid ethane cooled
by liquid nitrogen.
Grids were stored under liquid nitrogen.
3D Reconstruction
Reconstruction Method
HELICAL
Number of Particles
15504
Reported Resolution (Å)
20
Resolution Method
Other Details
three-dimensional single particle reconstruction
was carried out by a modification of the ihrsr method, using
spider. low-dose electron ...
three-dimensional single particle reconstruction
was carried out by a modification of the ihrsr method, using
spider. low-dose electron micrographs of 1008 frozen-hydrated
thick filaments halves were digitized at 0.248 nm per pixel
using a nikon super coolscan 8000 ed scanner. filaments were
aligned with the bare zone at the top, to ensure correct
polarity in subsequent steps. a total of 15,504 segments, each
62 nm long, with an overlap of 55.8 nm, and containing aprox.
40,000 unique pairs of interacting myosin heads went into the
reconstruction. as an initial reference model we used the
tarantula negatively stained 3d-map, which was axially
rotated, axially shifted and also out of plane tilted up to
plus-minus12deg. for projection matching, giving a total of 4,095
projections (13 tilted projections plus-minus 12 deg. every
2 deg., 45 reference rotated projections (0-90 deg., every 2 deg.
rotation angle), and 7 image axial shifts of 2.2 nm. the
resulting 3d-map combines about 10,700 out of 15,504 filament
segments, a yield of 69 percent of included segments.
Refinement Type
Symmetry Type
HELICAL
Map-Model Fitting and Refinement
Id
1 (1I84, 2FXM, 1B7T)
Refinement Space
REAL
Refinement Protocol
FLEXIBLE FIT
Refinement Target
Constrained Molecular Dynamics
Overall B Value
Fitting Procedure
Details
METHOD--Flexible Fitting REFINEMENT PROTOCOL--Custom skeleton of 31 positional
markers
Data Acquisition
Imaging Experiment
1
Date of Experiment
2001-09-19
Temperature (Kelvin)
88
Microscope Model
FEI/PHILIPS CM120T
Minimum Defocus (nm)
1950
Maximum Defocus (nm)
1950
Minimum Tilt Angle (degrees)
Maximum Tilt Angle (degrees)
Nominal CS
2
Imaging Mode
BRIGHT FIELD
Specimen Holder Model
Nominal Magnification
35000
Calibrated Magnification
35000
Source
LAB6
Acceleration Voltage (kV)
120
Imaging Details
Holey carbon grids Cryo preserved in Liquid ethane were observed in a Philips CM120 electron
microscope under low dose conditions. Only filaments on thin carbon over holes were photographed
