2q9g
Crystal structure of human cytochrome P450 46A1
OverviewOverview
Human cytochrome P450 46A1 (CYP46A1) is one of the key enzymes in cholesterol homeostasis in the brain. The crystallization and heavy-atom structure solution of an active truncated CYP46A1 in complex with the high-affinity substrate analogue cholesterol-3-sulfate (CH-3S) is reported. The 2.6 angstroms structure of CYP46A1-CH-3S was solved using both anion and cation heavy-atom salts. In addition to the native anomalous signal from the haem iron, an NaI anion halide salt derivative and a complementary CsCl alkali-metal cation salt derivative were used. The general implications of the use of halide and alkali-metal quick soaks are discussed. The importance of using isoionic strength buffers, the titration of heavy-atom salts into different ionic species and the role of concentration are considered. It was observed that cation/anion-binding sites will occasionally overlap, which could negatively impact upon mixed RbBr soaks used for multiple anomalous scatterer MAD (MMAD). The use of complementary cation and anion heavy-atom salt derivatives is a convenient and powerful tool for MIR(AS) structure solution.
About this StructureAbout this Structure
2Q9G is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Use of complementary cation and anion heavy-atom salt derivatives to solve the structure of cytochrome P450 46A1., White MA, Mast N, Bjorkhem I, Johnson EF, Stout CD, Pikuleva IA, Acta Crystallogr D Biol Crystallogr. 2008 May;64(Pt 5):487-95. Epub 2008, Apr 19. PMID:18453684 Page seeded by OCA on Wed Jun 18 12:03:17 2008