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

Abstract

The crystal structure of cytochrome P-450cam complexed with the enantiomer (lS)-camphor has been solved to 1.8 A 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 (lS)-enantiomer binds in at least two orientations. The major binding mode of (lS)-camphor resembles the one of the (lR)-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 (lS)-camphor is not hydrogen bonded, but C-5 is located suitably for hydroxylation.

CO as a vibrational probe of heme protein active sites

“…Although both have cysteinate ligands trans to the CO, the negatively charged sulfur atom is the recipient of different kinds of H-bonds. In cyt P450 cam , there are H-bonds from three backbone amide NH groups [63], while in NOS there are two such H-bonds plus an additional H-bond from a tryptophan sidechain [64][65][66]. This H-bond has been shown via mutagenesis to weaken the Fe-NO bond (lower mFeN) in the NO adduct [67], as would be expected from the thiolate becoming a stronger donor in the absence of a stablilizing H-bond.…”

The status of high-valent metal oxo complexes in the P450 cytochromes

“…While the effective stabilization of the Compound I intermediate, as defined by an oxo-ferryl p-cation radical species, has not been achieved in yields compatible with such techniques, a number of potential strategies are afforded. One traditional strategy is the functional redesign of the P450 enzyme through mutagenesis, either in the enhancement Crystals were obtained as described previously [98], diffraction data were collected with the crystal kept at 100 K and reduced with the XDS suite of programs [99]. The structures were refined using CNS [100] and REFMAC [101].…”

Second derivatives in generalized Born theory

“…We have measured the performance of the Newton-Raphson procedure using four molecular models. The molecular models were derived from the 1AKD, 28 Last row shows the speedup for 144 processors. Execution times (in seconds) are for the Newton-Raphson procedure using a a Sun Fire E25K server with 72 dual-core UltraSPARC IV processors.…”