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Structural Studies of Macromolecules in Solution using Small Angle X-Ray Scattering
Published on: November 5, 2018
A low-resolution low-temperature neutron diffraction study of myoglobin.
B V Daniels1, B P Schoenborn, Z R Korszun
1Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
Acta Crystallographica. Section D, Biological Crystallography
|August 10, 2004
Summary
This study measured myoglobin crystal expansion across temperatures, revealing a linear thermal expansion coefficient of 45 x 10(-6) K(-1) and identifying lattice disorder onset at 180 K.
Area of Science:
- Structural biology
- Biophysics
- Crystallography
Background:
- Understanding protein thermal expansion is crucial for structural biology.
- Myoglobin's hydration layers influence its crystal lattice dynamics.
Purpose of the Study:
- To determine the linear coefficient of thermal expansion for myoglobin.
- To investigate temperature-dependent changes in myoglobin crystal structure and hydration.
Main Methods:
- X-ray diffraction data collection at various temperatures (80 K to 240 K).
- Analysis of unit-cell parameter expansion to calculate thermal expansion coefficient.
- Shell solvent model application to describe hydration layers.
- Difference Fourier map calculations to identify structural changes.
Main Results:
- Myoglobin exhibits a linear thermal expansion coefficient of 45 x 10(-6) K(-1).
- A concerted lattice disorder effect, indicative of disorder onset, was observed at 180 K.
- Difference maps revealed minimal changes within the protein but significant features in the solvent region and at crystal lattice interfaces.
Conclusions:
- The shell solvent model provides a reasonable approximation for calculating myoglobin's thermal expansion.
- The study identifies 180 K as a critical temperature for the onset of extended lattice disorder in myoglobin crystals.
- Temperature-dependent diffraction analysis offers insights into protein crystal dynamics and hydration effects.
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