EMD-2322 Experiments and Validation

The bacterial DnaC helicase loader is a DnaB ring breaker

Single particle reconstruction
Overview of EMD-2322
Sample name: E. coli DnaB replicative helicase
Organism: Escherichia coli
Related EM entry by publication: EMD-2321

Map parameters

Minimum density: -6.672
Maximum density: 14.361
Average density: 0.00
Standard deviation: 1.00
Recommended contour level: 4.00 (author)

Sample information

Sample name: E. coli DnaB replicative helicase
Protein: DnaB replicative helicase

Validation information

Experimental information

 

Image processing

Applied symmetry: C3
Software: EMAN2, SPARX
Number of particles: 9617
Reconstruction protocol: Projection matching
CTF correction: Each micrograph

Imaging

Session
Microscope model: FEI TECNAI 12
Electron source: LAB6
Electron dose (e/A**2): 25.0
Nominal CS (mm): 6.30
Nominal magnification: 49000.0
Defocus max (nm): 1,200.00
Defocus min (nm): 700.00
Holder model: SIDE ENTRY, EUCENTRIC

Specimen

Preparation
Specimen state: particle
Buffer: 20 mM Tris-HCl pH 8.5, 200 mM NaCl, 5 % glycerol, 5 mM MgCl2, 1 mM beta-mercaptoethanol, and 1 mM ADP-BeF3
Staining procedure: Grids with adsorbed protein were floated on 2% w/v uranyl formate for 45 seconds
Specimen support: 400 mesh copper grid with thin carbon support, glow discharged for 20 seconds
Vitrification
Apparatus: NONE
Cryogen: NONE