Multi-wavelength anomalous dispersion

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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.[1] This method doesn't need two crystal structures (one native and one with heavy atom) for a unique phase solution. Instead anomalous diffraction is recorded at different wavelengths of coherent X-ray light at a synchrotron facility.

MAD was developed by Wayne Hendrickson while working as a postdoctoral researcher under Jerome Karle at the United States Naval Research Laboratory. [2] The mathematics upon which MAD (and progenitor Single wavelength anomalous dispersion) were based were developed by Jerome Karle, work for which he was awarded the 1985 Nobel Prize in Chemistry (along with Herbert Hauptman).

See also[edit]

Anomalous Dispersion[edit]

Isomorphous Replacement[edit]

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



  1. ^ Hendrickson W, Ogata C (1997). "Phase determination from multiwavelength anomalous diffraction measurements". Meth Enzymol. Methods in Enzymology 276: 494–523. doi:10.1016/S0076-6879(97)76074-9. ISBN 978-0-12-182177-7. 
  2. ^ Hendrickson WA (1985). "Analysis of Protein Structure from Diffraction Measurement at Multiple Wavelengths". Trans. ACA 21. 

Further reading[edit]

  • Hendrickson WA (1985). "Analysis of Protein Structure from Diffraction Measurement at Multiple Wavelengths". Trans. ACA 21. 
  • Karle J (1980). "Some Developments in Anomalous Dispersion for the Structural Investigation of Macromolecular Systems in Biology". International Journal of Quantum Chemistry: Quantum Biology Symposium 7: 357–367. 
  • Karle J (1989). "Linear Algebraic Analyses of Structures with One Predominant Type of Anomalous Scatterer". Acta Cryst. A45: 303–307. 
  • Pahler A, Smith JL, Hendrickson WA (1990). "A Probability Representation for Phase Information from Multiwavelength Anomalous Dispersion". Acta Cryst. A46: 537–540. 
  • Terwilliger TC (1994). "MAD Phasing: Bayesian Estimates of FA". Acta Cryst. D50: 11–16. 
  • Terwilliger TC (1994). "MAD Phasing: Treatment of Dispersive Differences as Isomorphous Replacement Information". Acta Cryst. D50: 17–23. 
  • Fourme R, Shepard W, Kahn R, l'Hermite G, de La Sierra IL (1995). "The Multiwavelength Anomalous Solvent Contrast (MASC) Method in Macrocolecular Crystallography". J. Synchrotron Rad. 2: 36–48. doi:10.1107/S0909049594006680. 
  • de la Fortelle E, Bricogne G (1997). "Maximum-Likelihood Heavy-Atom Parameter Refinement for Multiple Isomorphous Replacement and Multiwavelength Anomalous Diffraction Methods". Methods in Enzymology. Methods in Enzymology 276: 472–494. doi:10.1016/S0076-6879(97)76073-7. ISBN 978-0-12-182177-7. 
  • Hendrickson WA, Ogata CM (1997). "Phase Determination from Multiwavelength Anomalous Diffraction Measurements". Methods in Enzymology. Methods in Enzymology 276: 494–523. doi:10.1016/S0076-6879(97)76074-9. ISBN 978-0-12-182177-7. 
  • Bella J, Rossmann MG (1998). "A General Phasing Algorithm for Multiple MAD and MIR Data". Acta Cryst. D54: 159–174. 
  • 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:1988Sci...241..806G. doi:10.1126/science.3406739. PMID 3406739. 

External links[edit]

Computer programs[edit]

  • The SSRL Absorption PackageBrennan S, Cowan PL (1992). "A suite of programs for calculating x-ray absorption, reflection and diffraction performance for a variety of materials at arbitrary wavelengths". Rev. Sci. Instrum. 63: 850. Bibcode:1992RScI...63..850B. doi:10.1063/1.1142625. 
  • CHOOCHEvans G, Pettifer RF (2001). "CHOOCH: a program for deriving anomalous-scattering factors from X-ray fluorescence spectra". J. Appl. Cryst. 34: 82–86. doi:10.1107/S0021889800014655. 
  • Shake-and-Bake (SnB) — Smith GD, Nagar B, Rini JM, Hauptman HA, Blessing RH (1998). "The use of Snb to determine an anomalous scattering substructure". Acta Cryst D 54 (Pt 5): 799–804. doi:10.1107/S0907444997018805. PMID 9757093. 
  • SHELXSheldrick GM (1998). "SHELX: applications to macromolecules". In S Fortier. Direct methods for solving macromolecular structures. Dordrecht: Kluwer Academic Publishers. pp. 401–411. ISBN 0-7923-4949-0. 

Tutorials and examples[edit]