Detection of a High-Barrier Conformational Change in the Active Site of Cytochrome P450_(cam)upon Binding of Putidaredoxin

摘要

Cytochrome P450_(cam)(CYP101)catalyzes the 5-exo-hydroxylation of camphor 1,the first step of catabolism of 1 by the soil bacterium Pseudomonas putida.Two electrons are required for turnover,and the second reduction,of the Fe(II)P450_(cam)-O_2-1 ternary complex(CYP-1-O_2),is the rate-limiting step under physiological conditions.The presence of an effector is required for the formation of hydroxycamphor product.The Fe2S2 ferredoxin putidaredoxin(Pdx)is the biological effector and reductant of CYP101.Structural perturbations have been observed spectroscopically in the CYP101 active site upon binding of Pdx,and it has been proposed that these perturbations are involved in the effector and/or electron-transfer activity of Pdx.