Use of complementary cation and anion heavy-atom salt derivatives to solve the structure of cytochrome P450 46A1.

ABSTRACT: 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 cons

SUBMITTER: White MA 

PROVIDER: S-EPMC2467524 | biostudies-literature | 2008 May

REPOSITORIES: biostudies-literature