3JCJ

Structures of ribosome-bound initiation factor 2 reveal the mechanism of subunit association

ELECTRON MICROSCOPY

Sample
70S-fMet-tRNAiMet-IF2-GDPNP complex
Sample Components
70S ribosome
fMet-tRNAiMet
Initiation Factor 2

Specimen Preparation
Sample Aggregation State	PARTICLE
Vitrification Instrument	FEI VITROBOT MARK I
Cryogen Name	ETHANE
Sample Vitrification Details	Blot for 2-4 seconds before plunging into liquid ethane (FEI VITROBOT MARK I).

3D Reconstruction
Reconstruction Method	SINGLE PARTICLE
Number of Particles	54585
Reported Resolution (Å)	3.7
Resolution Method	FSC 0.143 CUT-OFF
Other Details	Final maps were calculated from two combined datasets. To avoid overfitting, the data were refined in a resolution-limited scheme using SPIDER.
Refinement Type
Symmetry Type	POINT
Point Symmetry	C1

Data Acquisition
Detector Type	GATAN K2 SUMMIT (4k x 4k)
Electron Dose (electrons/Å**2)	20

Imaging Experiment	1	2
Date of Experiment	2013-08-28	2015-06-10
Temperature (Kelvin)
Microscope Model	FEI POLARA 300	FEI POLARA 300
Minimum Defocus (nm)	640	190
Maximum Defocus (nm)	7180	7570
Minimum Tilt Angle (degrees)
Maximum Tilt Angle (degrees)
Nominal CS	2	2
Imaging Mode	BRIGHT FIELD	BRIGHT FIELD
Specimen Holder Model
Nominal Magnification	31000	31000
Calibrated Magnification	39000	39000
Source	FIELD EMISSION GUN	FIELD EMISSION GUN
Acceleration Voltage (kV)	300	300
Imaging Details

EM Software
Task	Software Package	Version
CTF CORRECTION	CTFFIND	4
RECONSTRUCTION	EMAN	2
RECONSTRUCTION	SPARX
RECONSTRUCTION	SPIDER

Image Processing
CTF Correction Type	CTF Correction Details	Number of Particles Selected	Particle Selection Details
	CTFFIND4

RCSB PDB Core Operations are funded by the National Science Foundation (DBI-1832184), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM133198.