Single wavelength anomalous dispersion

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Single-wavelength anomalous dispersion (abbreviated SAD) is a technique used in X-ray crystallography that facilitates the determination of the structure of proteins or other biological macromolecules by allowing the solution of the phase problem. In contrast to multi-wavelength anomalous dispersion, SAD uses a single dataset at a single appropriate wavelength. One advantage of the technique is the minimization of time spent in the beam by the crystal, thus reducing potential radiation damage to the molecule while collecting data.

[edit] See also

[edit] Anomalous Dispersion

• Multi-wavelength anomalous dispersion (MAD)
• Single wavelength anomalous dispersion (SAD)

[edit] Isomorphous Replacement

Two methods for providing the needed phasing information by introducing heavy atoms into isomorphous crystals:

• Multiple isomorphous replacement (MIR); and
• Single isomorphous replacement with anomalous signal (SIRAS)