Figure 14.2.1.1

Smith, J. L.; Hendrickson, W. A.

doi:10.1107/97809553602060000686

International
Tables for
Crystallography
Volume F
Crystallography of biological macromolecules
Edited by M. G. Rossmann and E. Arnold

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International Tables for Crystallography (2006). Vol. F. ch. 14.2, p. 300 | 1 | 2 |

Figure 14.2.1.1

J. L. Smith^a ^* and W. A. Hendrickson^b

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 ( $[E_{\rm edge}]$ ) is the inflection point of the $[\mu_a]$ (and [f''] ) spectrum, and $[E_{\rm peak}]$ is the energy of peak absorption just above the edge. These energies correspond to the wavelengths $[\lambda_{\rm edge}]$ and $[\lambda_{\rm peak}]$ in a MAD experiment because the magnitudes of [f'] and [f''] are greatest at $[E_{\rm edge}]$ and $[E_{\rm peak}]$ , respectively.