Studies of the biosynthesis of C50 carotenoids in Halobacterium cutirubrum.
Cells of Halobacterium cutirubrum were grown in the presence of [14C]mevalonate with and without 3 mM nicotine. Growth of cells was inhibited to a maximum extent of 25% but overall incorporation of 14C into total, neutral, or polar lipids was only inhibited about 16% during active growth and to a much lesser extent or not at all in stationary phase. Little effect of nicotine on labelling of squalenes, vitamin MK-8, geranylgeraniol, and phytoene was observed. However, labelling of bacterioruberin and monoanhydrobacterioruberin was extensively inhibited while that of lycopene and bisanhydrobacterioruberin was increased reciprocally by growth in the presence of 3 mM nicotine. Reincubation of the labelled nicotine-grown cells in fresh cold medium without nicotine restored the 14C-labelling of bacterioruberin and monoanhydrobacterioruberin at the expense of lycopene and bisanhydrobacterioruberin. These results confirm our previous findings suggesting that the C50 bacterioruberin is made by addition of a C5-isoprene unit to each end of the C40-lycopene chain, followed by introduction of four hydroxyl groups.
D002338:Carotenoids / Q000096:biosynthesis*; D003470:Culture Media; D006217:Halobacterium / Q000254:growth & development / Q000378:metabolism*; D008055:Lipids / Q000096:biosynthesis; D008798:Mevalonic Acid / Q000378:metabolism; D009538:Nicotine / Q000494:pharmacology; D013185:Squalene / Q000096:biosynthesis
D003470:Culture Media; D008055:Lipids; D002338:Carotenoids; D009538:Nicotine; D013185:Squalene; D008798:Mevalonic Acid