ELECTRON-TRANSFER FROM HIGH-POTENTIAL IRON-SULFUR PROTEIN AND LOW-POTENTIAL CYTOCHROME C-551 TO THE PRIMARY DONOR OF RUBRIVIVAX-GELATINOSUSREACTION-CENTER MUTATIONALLY DEVOID OF THE BOUND CYTOCHROME SUBUNIT
A. Osyczka et al., ELECTRON-TRANSFER FROM HIGH-POTENTIAL IRON-SULFUR PROTEIN AND LOW-POTENTIAL CYTOCHROME C-551 TO THE PRIMARY DONOR OF RUBRIVIVAX-GELATINOSUSREACTION-CENTER MUTATIONALLY DEVOID OF THE BOUND CYTOCHROME SUBUNIT, Biochimica et biophysica acta. Bioenergetics, 1321(1), 1997, pp. 93-99
The electron transfer reactions from low-potential cytochrome c-551, h
igh-potential iron-sulfur protein (HiPIP) and cytochrome c' to the pho
tosynthetic reaction center mutationally devoid of the bound cytochrom
e subunit in the C244 mutant of the purple bacterium Rubrivivax gelati
nosus were investigated using time-resolved optical spectroscopy. Cyto
chrome c-551 was the best electron donor. Both HiPIP and low-potential
cytochrome c-551 can also react with the bound cytochrome subunit, bu
t in this case HiPIP appeared to be more efficient than cytochrome c-5
51, Identification of soluble immediate electron donors to the bacteri
ochlorophyll dimer indicates that in Rvi. gelatinosus the bound cytoch
rome subunit is not essential for photosynthetic electron transport an
d growth. The presence of high-and low-potential electron carriers (Hi
PIP, E-m = 330 mV, and cytochrome c-551, E-m = 50 mV) involved in the
reduction of the bacteriochlorophyll dimer and the bound cytochrome su
bunit suggests that two alternative electron transfer pathways to the
photosynthetic reaction center may exist in Rvi. gelatinosus. (C) 1997
Elsevier Science B.V.