Substrate induced changes of the active site electronic states in reduced cytochrome P450 cam and the photolysis product of its CO complex

FEBS Letters

Greschner, S.¹  Jung, C.¹  Sharonov, Yu.A.² 

[1]Max-Delbrück-Centre for Molecular Medicine, 0-1115 Berlin-Buch, Germany

[2]Institute of Molecular Biology, Academy of Sciences of Russia, 117 984 Moscow, Russian Federation

关键词: Cytochrome P450;    Magnetic circular dichroism;    Low temperature;    Flash photolysis;    MCD;    magnetic circular dichroism;    HRP;    horseradish peroxidase;    P450 cam;    bacterial cytochrome P450 cam (CYP101 [1]);    P450 LM2;    microsomal cytochrome P450 LM2 (CYP2B2 [1]).;   

DOI  :  10.1016/0014-5793(93)81153-Q

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

MCD spectra of camphor-free and camphor-bound reduced cytochrome P450_cam have been recorded for the near UV and visible spectral regions at temperatures from 300K down to 2.1K and compared with those of the carbon monoxide photoproducts generated at 4.2K. In the absence of camphor, the reduced P450 is spectroscopically different from the photoproduct. In the presence of camphor, however, the spectra of the reduced P450 and of the photoproduct are almost similar and behave like the photoproduct of the camphor-free enzyme. This behavior indicates that substrate binding induces a higher active site rigidity. From the significant alteration of the temperature dependence of the MCD intensity for the reduced enzyme induced by camphor binding it is concluded that the near degeneracy of the electronic ground state in the substrate-free enzyme is removed by substrate binding.

【 授权许可】

Unknown