2q9g
From Proteopedia
Crystal structure of human cytochrome P450 46A1
Overview
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 Structure
2Q9G is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
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
