Determination of macromolecular structures from anomalous diffraction of synchrotron radiation.
Resonance between beams of x-ray waves and electronic transitions from bound atomic orbitals leads to a phenomenon known as anomalous scattering. This effect can be exploited in x-ray crystallographic studies on biological macromolecules by making diffraction measurements at selected wavelengths associated with a particular resonant transition. In this manner the problem of determining the three-dimensional structure of thousands of atoms is reduced to that of initially solving for a few anomalous scattering centers that can then be used as a reference for developing the entire structure. This method of multiwavelength anomalous diffraction has now been applied in a number of structure determinations. Optimal experiments require appropriate synchrotron instrumentation, careful experimental design, and sophisticated analytical procedures. There are rich opportunities for future applications.
Hendrickson
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Howard Hughes Medical Institute, Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032.
D003461:Crystallography / Q000379:methods*; D008958:Models, Molecular; D015394:Molecular Structure; D010315:Particle Accelerators; D011487:Protein Conformation; D014961:X-Ray Diffraction / Q000295:instrumentation*