Multi-wavelength anomalous diffraction (sometimes Multi-wavelength anomalous dispersion; abbreviated MAD) is a technique used in
X-ray crystallography
X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...
that facilitates the determination of the three-dimensional structure of biological macromolecules (e.g. DNA, drug receptors) via solution of the
phase problem
In physics, the phase problem is the problem of loss of information concerning the phase that can occur when making a physical measurement. The name comes from the field of X-ray crystallography, where the phase problem has to be solved for the de ...
.
MAD was developed by
Wayne Hendrickson
Wayne A. Hendrickson (born April 25, 1941, New York City) is an American biophysicist and University professor at Columbia. Dr. Hendrickson is a University Professor at Columbia University in the Department of Biochemistry and Molecular Biophysics ...
while working as a
postdoctoral research
A postdoctoral fellow, postdoctoral researcher, or simply postdoc, is a person professionally conducting research after the completion of their doctoral studies (typically a PhD). The ultimate goal of a postdoctoral research position is to pu ...
er under
Jerome Karle
Jerome Karle (born Jerome Karfunkle; June 18, 1918 – June 6, 2013) was an American physical chemist. Jointly with Herbert A. Hauptman, he was awarded the Nobel Prize in Chemistry in 1985, for the direct analysis of crystal structures using X-ra ...
at the
United States Naval Research Laboratory
The United States Naval Research Laboratory (NRL) is the corporate research laboratory for the United States Navy and the United States Marine Corps. It was founded in 1923 and conducts basic scientific research, applied research, technological ...
.
The mathematics upon which MAD (and progenitor
Single wavelength anomalous dispersion Single-wavelength anomalous diffraction (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 ...
) were based were developed by
Jerome Karle
Jerome Karle (born Jerome Karfunkle; June 18, 1918 – June 6, 2013) was an American physical chemist. Jointly with Herbert A. Hauptman, he was awarded the Nobel Prize in Chemistry in 1985, for the direct analysis of crystal structures using X-ra ...
, work for which he was awarded the 1985
Nobel Prize in Chemistry
)
, image = Nobel Prize.png
, alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then "M ...
(along with
Herbert Hauptman
Herbert Aaron Hauptman (February 14, 1917 – October 23, 2011) was an American mathematician and Nobel laureate. He pioneered and developed a mathematical method that has changed the whole field of chemistry and opened a new era in research in d ...
).
See also
*
Single wavelength anomalous dispersion Single-wavelength anomalous diffraction (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 ...
(SAD)
*
Multiple isomorphous replacement Multiple isomorphous replacement (MIR) is historically the most common approach to solving the phase problem in X-ray crystallography studies of proteins. For protein crystals this method is conducted by soaking the crystal of a sample to be analyz ...
(MIR)
*
Anomalous scattering Anomalous X-ray scattering (AXRS or XRAS) is a non-destructive determination technique within X-ray diffraction that makes use of the anomalous dispersion that occurs when a wavelength is selected that is in the vicinity of an absorption edge of on ...
*
Anomalous X-ray scattering Anomalous X-ray scattering (AXRS or XRAS) is a non-destructive determination technique within X-ray diffraction that makes use of the anomalous dispersion that occurs when a wavelength is selected that is in the vicinity of an absorption edge of on ...
*
Patterson map
References
Further reading
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External links
MAD phasing— an in depth tutorial with examples, illustrations, and references.
NRL Recognition of Nobel Prize
Computer programs
—
—
''Shake-and-Bake''
(''SnB'') —
SHELX
—
Tutorials and examples
*{{cite web , title=The method of Multiple wavelength Anomalous Diffraction using Synchrotron Radiation at optimal X-ray energies: Application to Protein Crystallography , first=Gwyndaf , last=Evans , work=PhD Thesis , date=October 1994 , publisher=University of Warwick , url=http://www.gwyndafevans.co.uk/thesis-html/thesis.html
Crystallography