Acta Crystallographica Section D

Biological Crystallography

Volume 58, Part 9 (September 2002)

research papers

Acta Cryst. (2002). D58, 1413-1420 [ doi:10.1107/S0907444902011010 ]

Xenon derivatization of halide-soaked protein crystals

S. Panjikar and P. A. Tucker

Abstract: Crystals of porcine pancreatic elastase can be derived by soaking in high-molarity bromide solutions. These crystals, either in a glycerol-based cryoprotectant solution or in paraffin oil, can be subsequently pressurized under a xenon atmosphere to incorporate xenon. When paraffin oil is used, a larger number of bromide ions are observed on the protein surface. Intensity data collected to lower energy than the bromine absorption edge can be used to determine the xenon position and the resultant phase information can be used to determine the bromine substructure from data collected to higher energy than the bromine absorption edge. The method would appear to have general applicability where large substructures need to be determined.

PDB references: 1l0z and 1l1g

Keywords: halide soaking; xenon derivatization.