Flow birefringence
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In biochemistry, flow birefringence is a hydrodynamic technique for measuring the rotational diffusion constants (or, equivalently, the rotational drag coefficients. The birefringence of a solution sandwiched between two concentric cylinders is measured as a function of the difference in rotational speed between the inner and outer cylinders. The flow tends to orient an ellipsoidal particle (typically, a protein, virus, etc.) in one direction, whereas rotational diffusion (tumbling) causes the molecule to become disoriented. The equilibrium between these two processes as a function of the flow provides a measure of the axial ratio of the ellipsoidal particle.
[edit] See also
Protein structure determination methods | ||
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High resolution: | X-ray crystallography | NMR | Electron crystallography | |
Medium resolution: | Cryo-electron microscopy | Fiber diffraction | Mass spectrometry | |
Spectroscopic: | NMR | Circular dichroism | Absorbance | Fluorescence | Fluorescence anisotropy | |
Translational Diffusion: | Analytical ultracentrifugation | Size exclusion chromatography | Light scattering | NMR | |
Rotational Diffusion: | Fluorescence anisotropy | Flow birefringence | Dielectric relaxation | NMR | |
Chemical: | Hydrogen-deuterium exchange | Site-directed mutagenesis | Chemical modification | |
Thermodynamic: | Equilibrium unfolding | |
Computational: | Protein structure prediction | Molecular docking | |
←Tertiary structure | Quaternary structure→ |