High impact information on Spheroidenone

• Unlike mutations that remove cbb(3) terminal oxidase activity or Rdx function, the PrrC deletion mutant shows no effect upon cbb(3) activity, nor does it affect the ratio of the carotenoid (Crt) spheroidene (SE) to spheroidenone (SO) [1].
• This effect was most pronounced when both the rdxB and the ccoP mutations were present together in cells cultured under nitrogen-fixing photosynthetic growth conditions in which spheroidenone represented approximately 90% of the total carotenoid [2].
• We have particularly shown that although the expression of most photosynthetic genes in R. capsulatus is repressed by oxygen, the crtA gene, located in the BamHI H fragment of the R' plasmid pRPS404 and responsible for the oxidation of spheroidene to spheroidenone, responds to oxygen in an opposite fashion [3].
• The optimal pH range for growth was 6.5-9.0 and the temperature optimum was 33 degrees C. The bacteria contained bacteriochlorophyll a and spheroidenone as the only carotenoid [4].
• The S(1)-mediated carotenoid-to- bacteriochlorophyll energy transfer efficiencies were determined to be 96%, 84%, and 73% for neurosporene, spheroidene, and spheroidenone, respectively [5].

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