ISSN:
1399-0047
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
The diffraction resolution of crystals of the guanine nucleotide-exchange factor complex, EF–Tu–Ts, has been extended from 5.0 to 2.5 Å by lowering the solvent content in the crystals as well as the temperature of data collection. The common form of EF–Tu–Ts crystal belongs to space group P212121 with a = 81.1, b = 109.9, c = 207.5 Å and has a solvent content of 61%. The crystals diffract to a resolution of 5.0 Å at 293 K and 4.0 Å at 273 K. When cryoprotective agents are slowly diffused into the crystals, the cell constants shrink to a = 74.4, b = 109.9, c = 198.7 Å and the solvent content falls to 55%. After the cryoprotective agent has been added, the crystals diffract to 2.7 Å resolution at 293 or 273 K and 2.5 Å at 250 K. X-ray diffraction data, collected before and after the transformation of individual EF–Tu–Ts crystals, demonstrate that a large percentage of the improvement in diffraction resolution is due solely to the addition of cryoprotective agents. The transfer procedures for the successful introduction of cryoprotective agents into EF–Tu–Ts crystals as well as the general applicability to other crystal systems will be discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0907444994001976
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