Bm3 from Bacillus megaterium

Another Class II P-450 redox system that has been extensively studied is the cytosolic flavocytochrome P-450 BM3 from Bacillus megaterium. BM3 is the fusion of a soluble P-450 domain with CPR." " " The FAD of BM3 is reduced by NADPH the electrons are transferred to FMN and then finally to the substrate-bound P-450 domain." " BM3 is the fastest reported P-450 monooxygenase,with the rate of hydride transfer from NADPH to FAD and the rate of electron transfer from FMN to heme several-fold above the mammalian P-450 redox systems." The structure of the full-length protein has yet to be solved, but the structure of the FAD- and NADPH-binding domain has been determined." This domain closely resembles rat liver CPR and contains several conserved residues implicated in NADPH binding and flavin reduction. 

Munro, A.W., K. Malarkey, J. McKnight, A.J. Xhomson, S.M. Kelly, N.C. Price et al. (1994). Xhe role of tryptophan 97 of cytochrome P450 BM3 from Bacillus megaterium in catalytic function. Evidence against the covalent switching hypothesis of P-450 electron transfer. Biochem. J. 303,423-428. 

Munro, A.W. (1994). The role of Tryptophan 97 of cytochrome P450 BM3 from Bacillus megaterium in catalytic function. Biochem. J. 303, 423-428. 

The same rational P450cam mutants which have already been described for limonene and pinene oxyfunctionalisations were also successfully applied to valencene. In whole-cell biotransformations -nootkatol and nootkatone formed as main products with up to 25% overall yield, corresponding to activities of up to 9.9 nmol (nmol P450) min [201]. Higher activities (up to 43 min ) but lower selectivities than those with P450cam were obtained with mutants derived from Bacillus megaterium P450 BM3. 

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