X-ray spectroscopy (XAS) contributes to structural biology in two ways. It can provide information on species for which crystal structures are not available and it can also provide supplemental information on systems for which crystal structures are available. Since about 30% of the human genome is made up of genes encoding metalloproteins, XAS, but in particular the extended X-ray absorption fine structure (EXAFS), is extremely useful to study the geometry of the metal’s vicinity within a radius of 5 Å. Its major strength is that very accurate values for bond lengths can be obtained, typically to better than ± 0.02 Å, which is comparable to accuracies obtained for small-molecule structures. These values are about ten times more accurate than those obtained from a typical protein crystallography experiment at a moderate resolution [3]. In EXAFS experiments multiple scattering (MS) occurs when multiple atoms backscatter photoelectrons. In this case, interference between the different backscattered waves can make the EXAFS sensitive to the relative arrangement of the atoms including some information on bond angles. Therefore the CMCF 08B1-1 beamline has been recently equipped with a four-element solid state detector, VORTEX-ME4, to perform EXAFS studies on protein crystals. Additionally, the BioXAS facility has been designed and is being built. It will be composed of two beamlines allowing the study of biological and health-related metals. These are important in diseases such as Alzheimer’s, environmental toxins, in metal-containing drugs, and as essential constituents of living systems.

1. Grochulski, P., Fodje, M.N., Gorin, J., Labiuk, S.L., and Berg, R. (2011) 08ID-1Beamline, the Prime Beamline at the Canadian Macromolecular Crystallography Facility. J. Appl. Cryst. In press.
2. Fodje, M. N., Berg, R., Black, G., Grochulski, P., & Janzen, K. (2010). Automation of the Macromolecular Crystallography Beamlines at the Canadian Light Source. PCaPAC, (pp. 130-132). Saskatoon.
3. DePristo, M.A., de Bakker, P.I.W. and Blundell, T.L. (2004) Heterogeneity and Inaccuracy in Protein Structures Solved by X-ray Crystallography. Structure 12, 831–838.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/24598 must be provided.