P450 BM3 Structure and Mechanism

Mutations in the active site of the enzyme can decrease the flavin-to-haem electron transfer rate to an extent that it is almost identical to the steady-state turnover rate of the enzyme (Noble et al., 1999). Also, problems with flavin fluorescence can be circumvented by studies of the haem domain of P450 BM3, and this has proven of great value for resonanee Raman characterisation of the haem site. One important finding from such studies has been that the active site of P450 BM3 is large enough to aeeommodate both a fatty acid and a large inhibitor molecule (metyrapone) simultaneously (Macdonald et al., 1996). 

FIGURE 5. The atomic structure of the haem domain of substrate-bound P450 BM3 (Li and Poulos, 1997). The major helices and sheets are shown, along with the haem macrocycle and active site-bound pahnitoleic acid in black. The overall shape of the molecule approximates a triangular prism. 

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