Interconversion of crystals of the Escherichia coli EF-Tu.EF-Ts complex between high- and low-diffraction forms.
Crystals of the complex formed between the two bacterial polypeptide elongation factors, EF-Tu and EF-Ts, produced from solutions of PEG 6000 can be of two morphologically similar forms both of space group P2(1)2(1)2(1). One form diffracts to only about 3 A resolution, the other to better than 2.4 A resolution. These forms can be interconverted and the transformation of one into the other has been shown to be solely a result of dehydration/hydration processes. By designing a suitable soaking protocol and careful control of the experimental parameters for data collection at cryotemperatures, complete data sets for the high-resolution form could be obtained.
EMBL Grenoble Outstation, Grenoble, France. tax@embl-grenoble.fr
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Kawashima
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Berthet-Colominas
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Cusack
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Leberman