Four (CYP195A2, CYP199A2, CYP203A1, and CYP153A5) of the seven P450 enzymes, and palustrisredoxin A; a ferredoxin associated with CYP199A2, from the metabolically diverse bacterium Rhodopseudomonas palustris have been expressed and purified. A range of substituted benzenes, phenols, benzaldehydes, and benzoic acids was shown to bind to the four P450 enzymes. Monooxygenase activity of CYP199A2 was reconstituted with palustrisredoxin A and putidaredoxin reductase of the P450cam system from Pseudomonas putida. We found that 4-ethylbenzoate and 4-methoxybenzoate were oxidized to single products; and 4-methoxybenzoate was demethy-lated to form 4-hydroxybenzoate. Crystals of substrate-free CYP199A2 which diffracted to similar to 2.0 angstrom have been obtained. (c) 2006 Elsevier Inc. All rights reserved.