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Partial rotational lattice order-disorder in stefin B crystals
Miha Renko1, Ajda Taler-Verčič1, Marko Mihelič1
1Department of Biochemistry and Molecular and Structural Biology, Josef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.
Summary
A novel partial rotational disorder in stefin B crystals was identified, impacting crystal lattice symmetry. This finding explains variations in diffraction data processing and crystal structure determination.
Area of Science:
- Crystallography
- Structural Biology
- Biophysics
Background:
- Crystal structure determination from twinned crystals is standard practice.
- Increasingly complex crystal lattice disorders are being observed.
- Stefins are small, basic proteins found in the saliva of humans and other animals.
Purpose of the Study:
- To describe a previously uncharacterized partial rotational order-disorder in stefin B crystals.
- To explain the observed diffraction patterns and processing anomalies.
- To elucidate the structural basis of the disorder.
Main Methods:
- X-ray diffraction data collection and processing.
- Crystal structure solution and refinement.
- Analysis of electron density maps.
Main Results:
- A unique five-tetramer layer crystal lattice structure for stefin B was determined.
- Four layers exhibit high order, while the fifth layer contains alternatively placed tetramers.
- The disorder leads to diffraction data consistent with space groups I4 and I422, with a preference for I4 under certain occupancy conditions.
Conclusions:
- The observed partial rotational order-disorder in stefin B crystals is a previously undescribed phenomenon.
- This disorder influences the apparent symmetry of the crystal lattice, affecting data processing.
- Understanding such disorders is crucial for accurate crystal structure determination and interpretation.
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