9MU8 | pdb_00009mu8

Structure of a native Drosophila melanogaster Pol II Elongation Complex without Rpb4/Rpb7 stalk

ELECTRON MICROSCOPY

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Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
in silico model	AlphaFold	P04052
in silico model	AlphaFold	P08266
in silico model	AlphaFold	O97183
in silico model	AlphaFold	Q9VEA5
in silico model	AlphaFold	Q7JZF5
in silico model	AlphaFold	Q24320
in silico model	AlphaFold	Q9VFB5
in silico model	AlphaFold	Q9VNZ3
in silico model	AlphaFold	P36958
in silico model	AlphaFold	Q9VC49
in silico model	AlphaFold	Q9VJE4
in silico model	AlphaFold	Q6IGE3

Refinement

RMS Deviations
Key	Refinement Restraint Deviation
f_dihedral_angle_d	14.685
f_angle_d	0.719
f_chiral_restr	0.049
f_plane_restr	0.006
f_bond_d	0.004

Sample
Native purified Pol II elongation complex from Drosophila melanogaster without the Rpb4/Rpb7 stalk

Specimen Preparation
Sample Aggregation State	PARTICLE
Vitrification Instrument	FEI VITROBOT MARK IV
Cryogen Name	ETHANE
Sample Vitrification Details

3D Reconstruction
Reconstruction Method	SINGLE PARTICLE
Number of Particles	96409
Reported Resolution (Å)	3.37
Resolution Method	FSC 0.143 CUT-OFF
Other Details
Refinement Type
Symmetry Type	POINT
Point Symmetry	C1

Map-Model Fitting and Refinement
Id	1
Refinement Space
Refinement Protocol	AB INITIO MODEL
Refinement Target
Overall B Value	50
Fitting Procedure
Details	The model was based on PDB: 6GML. First, 6GML was rigid-body fit in the cryo-EM Coulomb potential density map using UCSF ChimeraX. Next, AlphaFold2 models for individual Drosophila melanogaster Pol II subunits were aligned to their 6GML counterparts, and further optimized in the density using rigid-body fit. For the final model optimization, phenix.real_space_refine was used

Data Acquisition
Detector Type	FEI FALCON IV (4k x 4k)
Electron Dose (electrons/Å**2)	50.65

Imaging Experiment	1
Date of Experiment
Temperature (Kelvin)
Microscope Model	TFS TALOS
Minimum Defocus (nm)	1000
Maximum Defocus (nm)	2500
Minimum Tilt Angle (degrees)
Maximum Tilt Angle (degrees)
Nominal CS
Imaging Mode	BRIGHT FIELD
Specimen Holder Model	FEI TITAN KRIOS AUTOGRID HOLDER
Nominal Magnification
Calibrated Magnification
Source	FIELD EMISSION GUN
Acceleration Voltage (kV)	200
Imaging Details

EM Software
Task	Software Package	Version
PARTICLE SELECTION	cryoSPARC	4.3.1
IMAGE ACQUISITION	EPU	3.4
CTF CORRECTION	cryoSPARC	4.3.1
MODEL FITTING	UCSF ChimeraX	1.8
MODEL REFINEMENT	Coot	0.9.8.7
MODEL REFINEMENT	PHENIX	1.21.5207
INITIAL EULER ASSIGNMENT	cryoSPARC	4.3.1
FINAL EULER ASSIGNMENT	cryoSPARC	4.3.1
RECONSTRUCTION	cryoSPARC	4.3.1

Image Processing
CTF Correction Type	CTF Correction Details	Number of Particles Selected	Particle Selection Details
PHASE FLIPPING AND AMPLITUDE CORRECTION	'Patch CTF Estimation' in cryoSPARC	2349308	Initially, nearly 15 million particles were picked from micrographs. However, the number of particles cited here (2,349,308) is the starting number of particles after initial cleanup and 3D classification of the data.