title: Using barium ions for heavy-atom derivatization and phasing of xylanase II from Trichoderma longibrachiatum.
abstract: This paper describes the use of barium chloride to produce a heavy-atom derivative of xylanase II crystals from Trichoderma longibrachiatum, which was obtained either by cocrystallization or soaking. SAD phasing led to interpretable electron-density maps that allowed unambiguous chain tracing. In the best case, with a data set collected at 9.5 keV, 88% of the residues were built, with 83% of the side chains assigned. The barium ions are found to mainly interact with main-chain carbonyl groups and water molecules. It is suggested that barium ions could also be used as a potential anomalous scatterer in the quick cryosoaking procedure for phasing.
authors: National Synchrotron Light Source, Brookhaven National Laboratory, Building 725D, Upton, NY 11973, USA.
authors: Natalia
authors: N
authors: Moiseeva
authors: Marc
authors: M
authors: Allaire
mesh_terms: D001464:Barium / Q000737:chemistry*; D018360:Crystallography, X-Ray; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry*; D008958:Models, Molecular; D011487:Protein Conformation; D014242:Trichoderma / Q000201:enzymology*
chemical_list: D001464:Barium; D043364:Endo-1,4-beta Xylanases