Putidaredoxin reductase structure

P450cam from the soil bacterium Pseudomonas putida. The availability of large quantities of this stable and soluble enzyme, and its physiological electron transport cofactor proteins putidaredoxin reductase and putidaredoxin, made possible detailed spectroscopic and mechanistic investigations into P450 catalysis. P450cam was also the first P450 enzyme to be structurally characterized. ... 

The crystal structure of NADPH-cytochrome P450 reductase (CPR), the common electron-transfer protein of Class 11 eukaryotic P450 systems, was reported in 1997. This was followed by the structures of adrenodoxin reductase (AdR) and adrenodoxin (Adx), the two electron-transfer proteins of the Class 1 mitochondrial P450 system. The crystal structure of a cross-linked AdR-Adx complex has also been reported. " Putidaredoxin reductase (PdR) and putidaredoxin (Pd) of the P450cam system have also been structurally characterized. ... 

P450cam hydroxylates Ru-Cg-Ad when supplied with electrons via the natural NADH/putidaredoxin reductase/putd reduction relay.Ru-Cg-Ad hydroxylation occurs at only 1.6% the rate of camphor hydroxylation, and only 10% of the electrons supplied by NADH go to product formation. Presumably the rest are diverted to the formation of reduced oxygen species such as superoxide or hydrogen peroxide. The remarkable ability of P450cam to hydroxylate a molecule so structurally different from camphor supports the hypothesis that the structural flexibility inherent in the P450 fold allows these enzymes to hydroxylate structurally diverse substrates. 

Another recent advance in P450 electron transfer is the solution of both the putidaredoxin (Pdx) and putidaredoxin reductase (Pdr) crystal structures. Thus, the structure of all components of the P450cam monooxygenase system now are known. The Pdx and Pdr structures are... 

Figure 3.14. Structures of the adrenodoxin (Adx)-andrenodoxin reductase (Adr) complex, putidaredoxin (Pdx), and putidaredoxin reductase (Pdr). For comparisons, the structure of glutathione reductase also is shown.

Sevrioukova, I.F., H. Li, T.L. Poulos (2004). Crystal structure of putidaredoxin reductase from pseudomonas putida, the final structural component of the P450cam monooxygenase system. J. Mol. Biol. 236, 889-902. 

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