Publication Abstract from PubMed
Porcine pancreatic elastase has been crystallized at slightly acidic pH under two similar but slightly different conditions. Diffraction data were collected at a wavelength of 1.5 A to a maximum resolution of 1.7 A. Both difference electron-density maps and anomalous difference electron-density maps suggest that in crystals grown from a sodium sulfate solution PPE binds Na(+) in its metal-binding site. In contrast, PPE binds Ca(2+) in crystals grown from a solution containing sodium citrate and calcium chloride. This observation is in contradiction to most PPE structures reported in the PDB. In addition to the metal-binding site, up to three other binding sites, which appear to be anion-binding sites, could be identified based on the observed anomalous intensity differences.
Metal binding to porcine pancreatic elastase: calcium or not calcium.,Weiss MS, Panjikar S, Nowak E, Tucker PA Acta Crystallogr D Biol Crystallogr. 2002 Sep;58(Pt 9):1407-12. Epub 2002, Aug 23. PMID:12198296[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
