Electron transport in sulfate-reducing bacteria.

A hypothetical model of the complex formed between the iron-sulfur protein rubredoxin and the tetraheme cytochrome c₃ from the sulfate-reducing bacteria Desulfovibrio vulgaris (Hildenborough) has been proposed utilizing computer graphic modeling, computational methods and NMR spectroscopy. The proposed complex appears feasible on the basis of complementary electrostatic interaction and steric factors and is consistent with the data from NMR experiments. In this model, the non-heine iron atom of rubredoxin is in close proximity to heme 1 of cytochrome c₃. The complex is stabilized by charge-pair interactions and hydrogen bonds. This complex is compared to the flavodoxin-cytochrome c₃ complex previously proposed [Stewart, D. E., LeGall, J., Moura, I., Moura, J. J. G., Peck, H. D. Jr, Xavier, A. V., Weiner, P. K. & Wampler, J. E. (1988) Biochemistry 27, 24442450] and new NMR data shows that both proteins interact with the same heme group of the cytochrome as postulated. [ABSTRACT FROM AUTHOR]