CRYSTAL-STRUCTURE OF CYTOCHROME P450(CAM) COMPLEXED WITH ITS CATALYTIC PRODUCT, 5-EXO-HYDROXYCAMPHOR

The crystal structure of the enzyme-product complex formed between cyt ochrome P450(cam) and 5-exo-hydroxycamphor has been refined to 2.2 Ang strom and compared to the enzyme-substrate complex. The product occupi es the same position as the substrate with the exception that the prod uct 5-hydroxyl group forms a weak interaction with the heme iron atom as evidenced by continuous electron density between the product OH gro up and the iron atom. This interaction holds the heme iron in the low- spin configuration which prevents reduction of the heme iron by the ph ysiological electron donor, putidaredoxin. This also prevents the wast eful transfer of reducing equivalents to the product complex.