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Updated: Sep 9, 2026

Biochemical and Structural Characterization of the Carbohydrate Transport Substrate-binding-protein SP0092
Published on: October 2, 2017
Anomalous difference signal in protein crystals
Qun Shen1, Jun Wang, Steven E Ealick
1Cornell High Energy Synchrotron Source (CHESS), Wilson Laboratory, Cornell University, Ithaca, NY 14853, USA. qs11@cornell.edu
Abstract:
A scattering-angle-dependent formula is obtained for estimation of anomalous diffraction signals in Friedel pairs in protein crystals. In addition to the angle dependences of atomic form factor and temperature factor, a correlation form factor is introduced for the first time to take into account anomalous-scattering clusters such as disulfide bonds. Good agreements with experimental observations suggest that such correlated anomalous difference signals may be visible from measurements before a complete structural solution is obtained.
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