Multi-wavelength anomalous diffraction (sometimes Multi-wavelength anomalous dispersion; abbreviated MAD) is a technique used in X-ray crystallography that facilitates the determination of the three-dimensional structure of biological macromolecules (e.g. DNA, drug receptors) via solution of the phase problem.

MAD was developed by Wayne Hendrickson while working as a postdoctoral researcher under Jerome Karle at the United States Naval Research Laboratory. The mathematics upon which MAD (and progenitor Single-wavelength anomalous diffraction) was based were developed by Jerome Karle, work for which he was awarded the 1985 Nobel Prize in Chemistry (along with Herbert Hauptman).

Compared to the predecessor SAD, MAD has greatly elevated phasing power from using multiple wavelengths close to the edge. However, because it requires a synchrotron beamline, a longer exposure (risking radiation damage), and only allows a limited choice of heavy atoms (those with edges reachable by a synchrotron), MAD has declined in popularity relative to SAD.

See also

Further reading

  • Hendrickson WA (1985). "Analysis of Protein Structure from Diffraction Measurement at Multiple Wavelengths". Transactions of the ACA. 21.
  • Karle J (2009). "Some developments in anomalous dispersion for the structural investigation of macromolecular systems in biology". International Journal of Quantum Chemistry. 7: 357–367. doi:.
  • Karle J (1989). "Linear Algebraic Analyses of Structures with One Predominant Type of Anomalous Scatterer". Acta Crystallographica A. 45 (4): 303–307. Bibcode:. doi:. PMID .
  • Pahler A, Smith JL, Hendrickson WA (1990). "A Probability Representation for Phase Information from Multiwavelength Anomalous Dispersion". Acta Crystallographica A. 46 (7): 537–540. Bibcode:. doi:. PMID .
  • Terwilliger TC (1994). . Acta Crystallographica D. 50 (Pt 1): 11–16. Bibcode:. doi:. PMID .
  • Terwilliger TC (1994). . Acta Crystallographica D. 50 (Pt 1): 17–23. Bibcode:. doi:. PMID .
  • Fourme R, Shepard W, Kahn R, l'Hermite G, de La Sierra IL (1995). . Journal of Synchrotron Radiation. 2 (Pt 1): 36–48. Bibcode:. doi:. PMID .
  • de la Fortelle E, Bricogne G (1997). . Macromolecular Crystallography Part A. Methods in Enzymology. Vol. 276. pp. . doi:. ISBN 978-0-12-182177-7. PMID .
  • Hendrickson WA, Ogata CM (1997). . Macromolecular Crystallography Part A. Methods in Enzymology. Vol. 276. pp. . doi:. ISBN 978-0-12-182177-7. PMID .
  • Bella J, Rossmann MG (1998). "A General Phasing Algorithm for Multiple MAD and MIR Data". Acta Crystallographica D. 54 (2): 159–174. Bibcode:. doi:. PMID .
  • Guss JM, Merritt EA, Phizackerley RP, Hedman B, Murata M, Hodgson KO, Freeman HC (1989). "Phase determination by multiple-wavelength X-ray diffraction: crystal structure of a basic blue copper protein from cucumbers". Science. 241 (4867): 806–811. Bibcode:. doi:. PMID .

External links

  • — an in depth tutorial with examples, illustrations, and references.

Computer programs

  • — Brennan S, Cowan PL (1992). . Review of Scientific Instruments. 63 (1): 850. Bibcode:. doi:.
  • — Evans G, Pettifer RF (2001). "CHOOCH: a program for deriving anomalous-scattering factors from X-ray fluorescence spectra". Journal of Applied Crystallography. 34: 82–86. doi:.
  • (SnB) — Smith GD, Nagar B, Rini JM, Hauptman HA, Blessing RH (1998). "The use of Snb to determine an anomalous scattering substructure". Acta Crystallographica D. 54 (Pt 5): 799–804. Bibcode:. doi:. PMID .
  • — Sheldrick GM (1998). "SHELX: applications to macromolecules". In S Fortier (ed.). Direct methods for solving macromolecular structures. Dordrecht: Kluwer Academic Publishers. pp. 401–411. ISBN 0-7923-4949-0.{{cite book}}: CS1 maint: publisher location (link)

Tutorials and examples

  • Evans, Gwyndaf (October 1994). . PhD Thesis. University of Warwick.