Revelation of ternary complexes between redox partners in cytochrome P450-containing monooxygenase systems by the optical biosensor method.
Formation of binary and ternary complexes in the water-soluble cytochrome P450cam (P450cam)-containing as well as in the membrane P4502B4(2B4)- and the mixed P450scc-containing monooxygenase systems was investigated in real time by the 'resonant mirror' optical biosensor method. It was shown that the inter-protein electron transfer occurs not only during complex formation but also upon random collision--as was the case with the d-Fp/d-b5 pair (2B4 system). Binary complexes may be either facilitative to electron transfer (electron-transfer complexes) or prohibitive to it (non-productive complexes). Although the binary PdR/Pd and P450cam/Pd complex formation (within the P450cam-system) as well as the binary AdR/Ad and P450scc/Ad complex formation (within the P450scc-system) does occur, the lifetimes of these complexes formed are several orders of magnitude higher than the time required for realization of a complete hydroxylation cycle. At the same time, the lifetimes of the ternary PdR/Pd/P450cam and AdR/Ad/P450scc complexes are sufficient to permit the realization of a complete hydroxylation cycle in either of these systems. For the membrane P450 2B4 system, the formation of both the binary (Fp/2B4 and 2B4/b5) and ternary (Fp/2B4/b5) complexes was registered. The lifetimes of the binary Fp/2B4 and the ternary Fp/2B4/b5 complexes are sufficient for realization of a complete hydroxylation cycle in each of them.
Ivanov
Y D
YD
Institute of Biomedical Chemistry RAMS, Pogodinskaya St. 10, 119832, Moscow, Russia. yuiv@ibmh.msk.su
Kanaeva
I P
IP
Karuzina
I I
II
Usanov
S A
SA
Hui Bon Hoa
G
G
Sligar
S G
SG
Archakov
A I
AI
D015374:Biosensing Techniques / Q000379:methods; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry* / Q000302:isolation & purification; D004926:Escherichia coli; D007700:Kinetics; D055095:Optics and Photonics; D010084:Oxidation-Reduction
D003577:Cytochrome P-450 Enzyme System