Flash-freezing causes a stress-induced modulation in a crystal structure of soybean lipoxygenase l3.
A dynamic conformational flexibility of a protein might be a source of non-covalent structural heterogeneity, causing diminished diffracting ability of crystals and disorder in a crystal structure of soybean lipoxygenase L3. Room-temperature data, space group C2, correspond to a structure with large channels lined mostly or in part by disordered fragments of the molecule or flexible loops with an increased thermal vibration. A rapid change in temperature of approximately 200 K creates a wave of a stress-induced modulation that propagates in the crystal changing its reciprocal space into a three-dimensional quilt-like mixture of C and P intertwined lattices. Low-temperature data indicate a transformation from the dynamic to static disorder, leading to a primitive unit cell with 10% reduced volume. The molecules, formerly related by a twofold axis are rotated by approximately 7 degrees and are shifted along the diagonal to be approximately 4 A, closer together. During a routine data collection for the flash-frozen crystals of similar properties such phenomena could easily go unnoticed leading to biased results because of such effects and possibly improper indexing of the data.
Department of Chemistry, University of Toledo, OH 43606, USA. ejankun@uoft02.utoledo.edu
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Skrzypczak-Jankun
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Bianchet
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Mario Amzel
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Funk