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Primary photochemistry in the facultative green photosynthetic bacterium Chloroflexus aurantiacus
Author(s) -
Blankenship Robert E.,
Feick Reiner,
Bruce Barry D.,
Kirmaier Christine,
Holten Dewey,
Fuller R. Clinton
Publication year - 1983
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240220407
Subject(s) - bacteriochlorophyll , photochemistry , photosynthetic reaction centre , electron acceptor , chemistry , purple bacteria , redox , electron donor , electron transfer , photosynthesis , biochemistry , inorganic chemistry , catalysis
The mechanism of primary photochemistry has been investigated in purified cytoplasmic membranes and isolated reaction centers of Chloroflexus aurantiacus. Redox titrations on the cytoplasmic membranes indicate that the midpoint redox potential of P870, the primary electron donor bacteriochlorophyll, is +362 mV. An early electron acceptor, presumably menaquinone has E m 8.1 = −50 mV, and a tightly bound photooxidizable cytochrome c554 has E m 8.1 = +245 mV. The isolated reaction center has a bacteriochlorophyll to bacteriopheophytin ratio of 0.94:1. A two‐quinone acceptor system is present, and is inhibited by o‐phenanthroline. Picosecond transient absorption and kinetic measurements indicate the bacteriopheophytin and bacteriochlorophyll form an earlier electron acceptor complex.