Functional and spectral characterization of the respiratory chain ofChloroflexus aurantiacusgrown in the dark under oxygen-saturated conditions
✍ Scribed by Davide Zannoni; R. Clinton Fuller
- Book ID
- 104761506
- Publisher
- Springer
- Year
- 1988
- Tongue
- English
- Weight
- 684 KB
- Volume
- 150
- Category
- Article
- ISSN
- 0302-8933
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✦ Synopsis
In this paper we attempt a functional and spectral characterization of the membrane-bound cytochromes involved in respiratory electron transport by membranes from cells of Chloroflexus aurantiacus grown in the dark under oxygen saturated conditions. We conclude that the NADHdependent respiration is carried out by a branched respiratory chain leading to two oxidases which differ in sensitivity to CN-and CO. The two routes also show a different sensitivity to the ubiquinone analogue, HQNO, the pathway through the cytochrome e oxidase being fully blocked by 5 gM HQNO, whereas the "alternative" one is insensitive to this inhibitor. The cytochrome c oxidase containing branch is composed by at least two c-type haems with E,~ 7.0 of +130 and +270mV (c~ bands at 550/553 nm and 549 nm, respectively), plus a b-type cytochrome with Em 7.0 of + 50 mV (e band at 561 nm), From this, and previous work, we conclude that respiratory and photosynthetic electron transport components are assembled together and function on a single undifferentiated plasma membrane.