Crystal structure of cytochrome P‐450cam complexed with the (1S)‐camphor enantiomer

Abstract
The crystal structure of cytochrome P‐450cam complexed with the enantiomer (1S)‐camphor has been solved to 1.8 Å resolution and compared with the structure of the (1R)‐camphor P‐450cam complex. The overall protein structure is the same for both enantiomer complexes. However, the orientation of the substrates in the heme pocket differs. In contrast to (1R)‐camphor, the (1S)‐enantiomer binds in at least two orientations. The major binding mode of (1S)‐camphor resembles the one of the (1R)‐enantiomer in that there is a hydrogen bond between Tyr‐96 and the quinone group of camphor, and the 10‐methyl group points towards the I‐helix. The binding differs in that C‐5 is not at a position suitable for hydroxylation. In the other orientation (1S)‐camphor is not hydrogen bonded, but C‐5 is located suitably for hydroxylation.