7LNA

Infectious mammalian prion fibril (263K scrapie)

ELECTRON MICROSCOPY

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Refinement

RMS Deviations
Key	Refinement Restraint Deviation
r_dihedral_angle_2_deg	37.988
r_dihedral_angle_4_deg	19.307
r_dihedral_angle_3_deg	15.792
r_dihedral_angle_1_deg	6.356
r_angle_refined_deg	0.952
r_chiral_restr	0.045
r_bond_refined_d	0.012
r_gen_planes_refined	0.004
r_bond_other_d
r_angle_other_deg
r_gen_planes_other
r_nbd_refined
r_nbd_other
r_nbtor_refined
r_nbtor_other
r_xyhbond_nbd_refined
r_xyhbond_nbd_other
r_metal_ion_refined
r_metal_ion_other
r_symmetry_vdw_refined
r_symmetry_vdw_other
r_symmetry_hbond_refined
r_symmetry_hbond_other
r_symmetry_metal_ion_refined
r_symmetry_metal_ion_other
r_mcbond_it
r_mcbond_other
r_mcangle_it
r_mcangle_other
r_scbond_it
r_scbond_other
r_scangle_it
r_scangle_other
r_long_range_B_refined
r_long_range_B_other
r_rigid_bond_restr
r_sphericity_free
r_sphericity_bonded

Sample
infectious mammalian prion fibril (263K scrapie)

Specimen Preparation
Sample Aggregation State	FILAMENT
Vitrification Instrument	LEICA EM GP
Cryogen Name	ETHANE
Sample Vitrification Details

3D Reconstruction
Reconstruction Method	SINGLE PARTICLE
Number of Particles	15884
Reported Resolution (Å)	3.14
Resolution Method	FSC 0.143 CUT-OFF
Other Details	Auto-refinement was then performed while optimizing the helical twist and rise. Auto-refinement with refinement of twist and rise yielded a final map with a twist of -0.847 degree and rise of 4.874 angstrom. Iterative cycles of CTF refinement, Bayesian polishing, and auto refinement were used until resolution estimates stabilized. Post processing in RELION was performed with a soft-edged mask representing 10% of the central Z length of the fibril. Sharpening was applied with a B-factor of -31 square angstrom.
Refinement Type
Symmetry Type	POINT
Point Symmetry	C1

Map-Model Fitting and Refinement
Id	1
Refinement Space	RECIPROCAL
Refinement Protocol	AB INITIO MODEL
Refinement Target
Overall B Value
Fitting Procedure
Details

Data Acquisition
Detector Type	GATAN K3 BIOQUANTUM (6k x 4k)
Electron Dose (electrons/Å**2)	60

Imaging Experiment	1
Date of Experiment
Temperature (Kelvin)
Microscope Model	FEI TITAN KRIOS
Minimum Defocus (nm)
Maximum Defocus (nm)
Minimum Tilt Angle (degrees)
Maximum Tilt Angle (degrees)
Nominal CS
Imaging Mode	BRIGHT FIELD
Specimen Holder Model
Nominal Magnification
Calibrated Magnification
Source	FIELD EMISSION GUN
Acceleration Voltage (kV)	300
Imaging Details

EM Software
Task	Software Package	Version
PARTICLE SELECTION	RELION	3.1
IMAGE ACQUISITION	SerialEM
CTF CORRECTION	CTFFIND	4.1
MODEL FITTING	Coot	0.9.2pre
MODEL FITTING	PHENIX	1.19
MODEL REFINEMENT	PHENIX	1.19
MODEL REFINEMENT	REFMAC	5
INITIAL EULER ASSIGNMENT	RELION	3.1
FINAL EULER ASSIGNMENT	RELION	3.1
CLASSIFICATION	RELION	3.1
RECONSTRUCTION	RELION	3.1

Image Processing
CTF Correction Type	CTF Correction Details	Number of Particles Selected	Particle Selection Details
PHASE FLIPPING AND AMPLITUDE CORRECTION		337368	Filament start and end positions were picked manually in RELION. Particles were extracted with an interbox distance of 14.7A along the filament axis.