International
Tables for Crystallography Volume F Crystallography of biological macromolecules Edited by M. G. Rossmann and E. Arnold © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. F. ch. 14.2, p. 300
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Figure 14.2.1.1
Anomalous scattering factors for Se in a protein labelled with selenomethionine. The spectra are a hybrid of experimental values derived from an absorption spectrum of a SeMet protein for energies near the Se K absorption edge and calculated values for energies remote from the edge. The Se K edge occurs at 12 660 eV, corresponding to a wavelength of 0.9800 Å. Anomalous-scattering effects are enhanced by a white line just above the edge. The position of the absorption edge () is the inflection point of the (and ) spectrum, and is the energy of peak absorption just above the edge. These energies correspond to the wavelengths and in a MAD experiment because the magnitudes of and are greatest at and , respectively. |