2BG9
REFINED STRUCTURE OF THE NICOTINIC ACETYLCHOLINE RECEPTOR AT 4A RESOLUTION.
ELECTRON MICROSCOPY
| Sample |
|---|
| NICOTINIC ACETYLCHOLINE RECEPTOR in postsynaptic membrane |
| Specimen Preparation | |
|---|---|
| Sample Aggregation State | HELICAL ARRAY |
| Vitrification Instrument | |
| Cryogen Name | |
| Sample Vitrification Details | LIQUID ETHANE |
| 3D Reconstruction | |
|---|---|
| Reconstruction Method | HELICAL |
| Number of Particles | |
| Reported Resolution (Å) | |
| Resolution Method | |
| Other Details | |
| Refinement Type | |
| Symmetry Type | HELICAL |
| Data Acquisition | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Detector Type | KODAK SO-163 FILM | ||||||||
| Electron Dose (electrons/Å**2) | |||||||||
| Imaging Experiment | 1 |
|---|---|
| Date of Experiment | 2000-10-01 |
| Temperature (Kelvin) | 4.2 |
| Microscope Model | JEOL 3000SFF |
| Minimum Defocus (nm) | 800 |
| Maximum Defocus (nm) | 1800 |
| Minimum Tilt Angle (degrees) | |
| Maximum Tilt Angle (degrees) | |
| Nominal CS | 1.3 |
| Imaging Mode | BRIGHT FIELD |
| Specimen Holder Model | |
| Nominal Magnification | 40000 |
| Calibrated Magnification | 36800 |
| Source | FIELD EMISSION GUN |
| Acceleration Voltage (kV) | 300 |
| Imaging Details | THE SPECIMENS WERE TUBULAR CRYSTALS GROWN IN LOW SALT BUFFER FROM ISOLATED TORPEDO POSTSYNAPTIC MEMBRANES. THEY WERE APPLIED TO THE MICROSCOPE GRIDS AND FROZEN IN THE SAME SOLUTION. THESE CRYSTALS WERE TOO SMALL AND DISTORTED TO YIELD MEANINGFUL ELECTRON DIFFRACTION PATTERNS, SO BOTH THE AMPLITUDE AND THE PHASE TERMS HAD TO BE MEASURED FROM FOURIER TRANSFORMS OF THE IMAGES. THE IMAGES WERE RECORDED USING A DOSE OF 2000 ELECTRONS/NM2 DURING THE PERIOD: JAN-1996 TO OCT-2002. THE DATASETS INVOLVED 4 HELICAL FAMILIES OF TUBES. STRUCTURES WERE SYNTHESISED FROM THE AMPLITUDE AND PHASE TERMS DERIVED FROM EACH FAMILY. THE FINAL DATASET WAS OBTAINED BY AVERAGING THESE 4 STRUCTURES IN REAL SPACE. |
