Direct methods in crystallography by C. Giacovazzo
نویسندگان
چکیده
منابع مشابه
Direct methods for surface crystallography
In the most developed branches of crystallography, structure solution proceeds by two distinct steps: first, an approximate model of the structure is deduced directly from the measured data by an algorithm which assumes no preconceived model; second, a process of structure refinement simulates the experimental data for systematic variations of the parameters of such a model and determines a fin...
متن کاملAdvances in direct methods for protein crystallography.
Recent advances in ab initio direct methods have enabled the solution of crystal structures of small proteins from native X-ray data alone, that is, without the use of fragments of known structure or the need to prepare heavy-atom or selenomethionine derivatives, provided that the data are available to atomic resolution. These methods are also proving to be useful for locating the selenium atom...
متن کاملDirect Methods of Structure Analysis in Polymer Crystallography
The use of direct phasing techniques, of the type familiar to small molecule x-ray crystallographers, for solving polymer crystal structures is discussed. Single crystal intensities from electron diffraction experiments are particularly useful, especially if the complete reciprocal lattice can be sampled. Furthermore, the analysis of powder or fiber x-ray data also is not precluded, especially ...
متن کاملDirect methods and protein crystallography at low resolution.
The tools of modern direct methods are examined and their limitations for solving protein structures discussed. Direct methods need atomic resolution data (1.1-1.2 A) for structures of around 1000 atoms if no heavy atom is present. For low-resolution data, alternative approaches are necessary and these include maximum entropy, symbolic addition, Sayre's equation, group scattering factors and el...
متن کاملTowards direct phase retrieval in macromolecular crystallography.
and G. Stubbs. 1985. Solving the phase problem in fiber diffraction. Application to tobacco mosaic virus at 3.6 A resolution. Acta Crystallogr. (Sect. A). 41:252-262. Smith, P. J. C., and S. Arnott. 1978. LALS: A linked-atom least-squares reciprocal-space refinement system incorporating stereochemical restraints to supplement sparse diffraction data. Acta Crystallogr. (Sect. A). 34:3-11. Stubbs...
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ژورنال
عنوان ژورنال: Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry
سال: 1981
ISSN: 0567-7408
DOI: 10.1107/s0567740881007280