Kinetics studies of the superoxide-mediated electron transfer reactions between rubredoxin-type proteins and superoxide reductases

Citation:
Auchere, F., S. R. Pauleta, P. Tavares, I. Moura, and JJG Moura. "Kinetics studies of the superoxide-mediated electron transfer reactions between rubredoxin-type proteins and superoxide reductases." Journal of Biological Inorganic Chemistry. 11 (2006): 433-444.

Abstract:

In this work we present a kinetic study of the superoxide-mediated electron transfer reactions between rubredoxin-type proteins and members of the three different classes of superoxide reductases (SORs). SORs from the sulfate-reducing bacteria Desulfovibrio vulgaris (Dv) and D. gigas (Dg) were chosen as prototypes of classes I and II, respectively, while SOR from the syphilis spyrochete Treponema pallidum (Tp) was representative of class III. Our results show evidence for different behaviors of SORs toward electron acceptance, with a trend to specificity for the electron donor and acceptor from the same organism. Comparison of the different k (app) values, 176.9 +/- 25.0 min(-1) in the case of the Tp/Tp electron transfer, 31.8 +/- 3.6 min(-1) for the Dg/Dg electron transfer, and 6.9 +/- 1.3 min(-1) for Dv/Dv, could suggest an adaptation of the superoxide-mediated electron transfer efficiency to various environmental conditions. We also demonstrate that, in Dg, another iron-sulfur protein, a desulforedoxin, is able to transfer electrons to SOR more efficiently than rubredoxin, with a k (app) value of 108.8 +/- 12.0 min(-1), and was then assigned as the potential physiological electron donor in this organism.

Notes:

Times Cited: 11 Auchere, F Pauleta, SR Tavares, P Moura, I Moura, JJG

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