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Cytochrome c ‐549 ‐ an endogenous cofactor of cyclic photophosphorylation in the cyanobacterium Anacystis nidulans ?
Author(s) -
Kienzl Peter F.,
Peschek Günter A.
Publication year - 1983
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(83)81052-7
Subject(s) - photophosphorylation , ferredoxin , cytochrome , plastoquinone , cytochrome c , cofactor , chemistry , electron transport chain , cytochrome b6f complex , biochemistry , biology , photochemistry , photosynthesis , chloroplast , photosystem i , enzyme , mitochondrion , photosystem ii , thylakoid , gene
The cyanobacterium Anacystis nidulans synthesizes fairly large amounts of low potential cytochrome c ‐549 ( E ′ o = −260 mV) during late logarithmic and stationary growth phases. We show here that isolated cytochrome c ‐549 catalyzed high rates of cyclic photophosphorylation by membrane preparations of A. nidulans when added in about 50% reduced state; fully oxidized or reduced cytochrome c ‐549 was far less efficient. A similarly decisive role of proper redox poising was documented with ferredoxin as the cofactor of cyclic photophosphorylation. Inhibitor studies indicated that plastoquinone and cytochrome f are involved in cyclic electron flow catalyzed by cytochrome c ‐549 and ferredoxin.