Time‐resolved Fourier‐transform infrared studies of the cytochrome P‐450cam carbonmonoxide complex bound with (1R)‐camphor and (1S)‐camphor substrate

FEBS Letters

Jung, Christiane¹  Ristau, Otto¹  Contzen, Jörg¹ 

[1] Max-Delbrück-Centrum für Molekulare Medizin, Robert-Rössle-Straβe 13122 Berlin, Germany

关键词: Cytochrome P-450cam;    Flash photolysis;    Carbon monoxide;    Substrate interaction;    Infrared;    Thermodynamic parameter;    P-450cam;    cytochrome P-450 from Pseudomonas putida (CYP101);    P-450cam(1R);    (1R)-camphor bound form of cytochrome P-450cam;    Mb;    myoglobin;    P-450nor;    cytochrome P-450 from Fusarium oxysporum;    FTIR;    Fourier-transform infrared;   

DOI  :  10.1016/0014-5793(96)00103-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The CO-binding reaction of cytochrome P-450_cam bound with (1R)-camphor and (1S)-camphor are compared in the temperature region of 210–260 K using time-resolved Fourier-transform infrared spectroscopy with the CO stretch vibration as spectroscopic probe. For (1S)-camphor as substrate the association of CO is slowed down by a factor of 2, while the dissociation is accelerated by a factor of 3. The CO complex for the (1S)-camphor-bound P-450 is less stabilized (ΔG=−22 kJ/mol) compared to the natural substrate (1R)-camphor (ΔG=−30 kJ/mol). The data are interpreted by a smaller change of the mobility of the (1S)-camphor due to CO binding as compared to (1R)-camphor, which would indicate a higher mobility of (1S)-camphor already in the CO free reduced form of P-450_cam. The higher mobility of (1S)-camphor in the heme pocket might explain the increased uncoupling rate (hydrogen peroxide formation) of 11% [Maryniak et al. (1993) Tetrahedron 49, 9373–9384] during the P-450_cam catalyzed hydroxylation compared to 3% for the conversion of (1R)-camphor.

【 授权许可】

Unknown