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Holographic methods in X-ray crystallography. IV. A fast algorithm and its application to macromolecular
J R Somoza1, H Szöke, D M Goodman
1Department of Chemistry and Lawrence Berkeley Laboratory, University of California, Berkeley 94720, USA.
Acta Crystallographica. Section A, Foundations of Crystallography
|September 1, 1995
Summary
A new fast algorithm enables the holographic method for large crystal structures. This technique recovers missing electron density, showing promise for macromolecular X-ray crystallography applications.
Area of Science:
- Crystallography
- X-ray diffraction
- Computational chemistry
Background:
- The holographic method aids in reconstructing crystal structures by combining partial models with experimental data.
- Current limitations exist in applying this method to large-scale crystallographic problems.
Purpose of the Study:
- To develop and present a fast algorithm for the holographic method applicable to sizable crystallographic challenges.
- To evaluate the utility of this enhanced holographic method for macromolecular X-ray crystallography.
Main Methods:
- A novel algorithm is introduced that utilizes positivity constraints on electron density.
- The algorithm incorporates a 'target' electron density, analogous to solvent flattening techniques.
- The method was tested using both synthetic and experimental crystallographic data.
Main Results:
- The developed algorithm significantly accelerates the application of the holographic method.
- The method successfully recovers electron density for the unmodeled portions of crystal structures.
- Initial assessments indicate potential for macromolecular X-ray crystallography.
Conclusions:
- The fast algorithm enhances the practicality of the holographic method for complex crystallographic systems.
- The approach shows promise as a valuable tool in macromolecular structure determination.
- Further application in X-ray crystallography is warranted.
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