Putidaredoxin-cytochrome P450cam interaction

Cytochrome P450cam (P450cam) catalyzes the monooxygenation of D-camphor. Du ring the enzymatic reaction, oxyferrous, D-camphor-bound P450cam forms a bi nary complex with reduced putidaredoxin as an obligatory reaction intermedi ate. We have found that reduced putidaredoxin undergoes EPR-detectable conf ormational changes upon formation of the intermediate complex and also upon formation of a binary complex with CO- or NO-ferrous, D-camphor-bound P450 cam. The structural changes in putidaredoxin are almost identical irrespect ive of the ligand bound to P450cam, and distinct from and significantly lar ger than those induced by unliganded ferrous P450cam. The binary complex fo rmation also induce conformational alterations in the CO- and NO-ferrous, D -camphor-bound P450cam. thereby evoking simultaneous changes in the structu re of the two proteins. A molecular basis and roles of such structural chan ges in the D-camphor monooxygenation are discussed. (C) 2001 Elsevier Scien ce B.V. All rights reserved.