| Newsletter No. 250
|| December 5, 2011
| TIPS AND TRICKS - Small Molecule Crystal Data Collection
Bernard D Santarsiero: You can collect 5-10deg images, and go ahead and collect 360deg. I usually use 1-3 seconds exposures, depending on the diffraction. The detector is set as close as possible, to get data to 0.8-0.9A resolution. For a MAR CCD 300mm detector, that's around 90-100mm, with the wavelength set at 0.8A, or around 15.5KeV in energy. You can process it with HKL2000 or XDS easily.
Zbigniew Dauter: I completely agree with Bernard, but I have one additional comment. The range of intensities from small molecule crystals is usually much higher than from protein crystals. It is therefore practically always necessary to collect them in multiple (sometimes even three) passes with different effective exposure time (or beam attenuation) and resolution range. Unfortunately people often forget about it and as a result very many strongest reflections are overloaded and lost.
ARCHIVE: Introduction, Pre-crystallization, Crystallization, Post-crystallization, Derivatization, Cryoprotection, Diffraction, Symmetry, Structure Solution, Structure Refinement, Structure Analysis & Presentation.
DISCUSSION - Suggested Topic?
ARCHIVE: Test-set-and-R-free, Twinning, Low Resolution Crystallography, PHASER, HKL2000, Parallel Expression, Structural Genomics, NCS, Missing Atoms, Trends in Crystallography, Absorption Correction.
| DR. ZBIGNIEW DAUTER'S LECTURE AT
THE NIH (2005)
Part 1: "How to read international tables?"
Part 2: "Data collection strategy" and "Twinning"
"Phasing methods - a general introduction to all methods"
Part 3: "SAD phasing, Quick halide soaking, and Radiation damage
with possible use of it for phasing"
Databases: BMCD, CryoD, DisProt, ExPASy, HAD, HIC-Up, Metal Sites, NDB, PDB, PDBe,
Programs: CCP4, COOT, HKL, PHENIX, PyMOL, SOLVE, USF, XDS
Servers: CheckMyMetal, Crystal, C6, Dali, ESPript, Phyre, Probity, Protein
|Copyright © NIH X-Ray Diffraction Group Maintained by Dr. Xinhua Ji|
|on the NIH-NCI-CCR-MCL server (http://mcl1.ncifcrf.gov)|