ISSN:
1432-1327
Keywords:
Key words Cytochrome c3
;
Electron transfer
;
Proton transfer
;
Redox-Bohr
;
Energy transduction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract A central step in the metabolism of Desulfovibrio spp. is the oxidation of molecular hydrogen catalyzed by a periplasmic hydrogenase. However, this enzymatic activity is quite low at physiological pH. The hypothesis that, in the presence of the tetrahaem cytochrome c 3, hydrogenase can maintain full activity at physiological pH through the concerted capture of the resulting electrons and protons by the cytochrome was tested for the case of Desulfovibrio vulgaris (Hildenborough). The crucial step involves an electron-to-proton energy transduction, and is achieved through a network of cooperativities between redox and ionizable centers within the cytochrome (redox-Bohr effect). This mechanism, which requires a relocation of the proposed proton channel in the hydrogenase structure, is similar to that proposed for the transmembrane proton pumps, and is the first example which shows evidence of functional energy transduction in the absence of a membrane confinement.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s007750050160
