9NWT | pdb_00009nwt

Cryo-EM structure of DDB1dB:CRBN:mezigdomide:SALL4(392-449;G416A)


ELECTRON MICROSCOPY

Starting Model(s)

Initial Refinement Model(s)
TypeSourceAccession CodeDetails
experimental modelPDB 8TNQ 
experimental modelPDB 8U17 
experimental modelPDB 8D7Z 

Refinement

RMS Deviations
KeyRefinement Restraint Deviation
f_dihedral_angle_d8.4236
f_angle_d0.4188
f_chiral_restr0.0436
f_plane_restr0.0069
f_bond_d0.0018
Sample
Ternary complex of DDB1dB:CRBN:mezigdomide:SALL4(392-449;G416A)
Specimen Preparation
Sample Aggregation StatePARTICLE
Vitrification InstrumentLEICA EM GP
Cryogen NameETHANE
Sample Vitrification DetailsUltrAuFoil R 0.6/1 300 mesh grids were glow-discharged for 2 min at 20 mA and 39 Pa, pre-incubated with 4 uL of 10 uM FLAG-IKZF1(140-196;Q146A/G151N) ...UltrAuFoil R 0.6/1 300 mesh grids were glow-discharged for 2 min at 20 mA and 39 Pa, pre-incubated with 4 uL of 10 uM FLAG-IKZF1(140-196;Q146A/G151N) for 1 min, and blotted from behind for 4 s. 4 uL of the sample was then applied to the grid. Grids were vitrified using an EM GP plunge freezer operated at 90% humidity and 10 C with 0 s pre-blot, 4 s blot, and 0 s post-blot.
3D Reconstruction
Reconstruction MethodSINGLE PARTICLE
Number of Particles479953
Reported Resolution (Å)2.7
Resolution MethodFSC 0.143 CUT-OFF
Other DetailsParticles were re-extracted at 0.83 A/pixel, and subsequently processed by reference-based motion correction and global CTF refinement (per-group beam ...Particles were re-extracted at 0.83 A/pixel, and subsequently processed by reference-based motion correction and global CTF refinement (per-group beam tilt and trefoil). Homogeneous refinement of these processed particles followed by local refinement with a mask encompassing the full particle yielded a final reconstruction at 2.7 A. A local refinement using the CRBN:drug:ZF-focused mask further improved drug and ZF density.
Refinement Type
Symmetry TypePOINT
Point SymmetryC1
Map-Model Fitting and Refinement
Id1 (8TNQ, 8TNQ, 8U17, 8D7Z)
Refinement SpaceREAL
Refinement Protocol
Refinement Target
Overall B Value
Fitting Procedure
DetailsSharpened and unsharpened maps processed by cryoSPARC, in addition to maps post-processed with DeepEMhancer (v0.16), were used for model building. A p ...Sharpened and unsharpened maps processed by cryoSPARC, in addition to maps post-processed with DeepEMhancer (v0.16), were used for model building. A previously-built model of DDB1dB:CRBN:mezigdomide:SALL4(392-449) was fit into the density as individual chains using ChimeraX (v1.6.1). Using the same ligand restraint file described above, the model was relaxed into the density using Rosetta (v3.13) followed by manual adjustment in Coot. The model was prepared for refinement using phenix.ready_set (v1.21-5207) and refined using phenix.real_space_refine (v1.21-5207).
Data Acquisition
Detector TypeGATAN K3 BIOQUANTUM (6k x 4k)
Electron Dose (electrons/Å**2)55.3
Imaging Experiment1
Date of Experiment
Temperature (Kelvin)
Microscope ModelTFS KRIOS
Minimum Defocus (nm)1000
Maximum Defocus (nm)2400
Minimum Tilt Angle (degrees)
Maximum Tilt Angle (degrees)
Nominal CS2.7
Imaging ModeBRIGHT FIELD
Specimen Holder ModelFEI TITAN KRIOS AUTOGRID HOLDER
Nominal Magnification105000
Calibrated Magnification
SourceFIELD EMISSION GUN
Acceleration Voltage (kV)300
Imaging Details
EM Software
TaskSoftware PackageVersion
PARTICLE SELECTIONTopaz0.2.5
IMAGE ACQUISITIONSerialEM4.1b
CTF CORRECTIONcryoSPARC4.2.0
MODEL FITTINGUCSF ChimeraX1.6.1
INITIAL EULER ASSIGNMENTcryoSPARC4.2.0
FINAL EULER ASSIGNMENTcryoSPARC4.2.0
CLASSIFICATIONcryoSPARC4.2.0
RECONSTRUCTIONcryoSPARC4.2.0
MODEL REFINEMENTPHENIX1.21-5207
Image Processing
CTF Correction TypeCTF Correction DetailsNumber of Particles SelectedParticle Selection Details
PHASE FLIPPING AND AMPLITUDE CORRECTION9479675Particles were picked using Topaz (v0.2.5) trained on templates from on-the-fly 2D classification