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Difference structure‐factor normalization for heavy‐atom or anomalous‐scattering substructure determinations
Author(s) -
Blessing Robert H.,
Smith G. David
Publication year - 1999
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889899003416
Subject(s) - substructure , anomalous scattering , phaser , scattering , normalization (sociology) , physics , multiple isomorphous replacement , atom (system on chip) , structure factor , crystallography , chemistry , molecular physics , optics , x ray crystallography , diffraction , computer science , structural engineering , sociology , anthropology , engineering , embedded system
Procedures are described for normalizing structure‐factor difference magnitudes, |Δ| F || SIR = || F Der | − | F Nat || ≤ | F Heavy | or |Δ| F || SAS = || F + h | − | F − h || ≤ 2| F ′′|, to prepare data for probabilistic direct methods phasing to determine heavy‐atom or anomalous‐scattering substructures in SIR (single‐derivative isomorphous replacement) or SAS (single‐wavelength anomalous scattering) cases. Applications of the procedures in several recent determinations of multi‐selenium substructures in selenomethionyl proteins via SnB direct‐methods phasing are briefly summarized.