Biosynthesis of Carotenoids in Purple Bacteria : A Re-Evaluation Based on Considerations of Chemical Structure

Jensen, Synnøve Liaaen; Cohen-Bazire, Germaine; Stanier, Roger Y.

doi:10.1038/1921168a0

Cited by 78 publications

(26 citation statements)

References 23 publications

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“…The Crt biosynthetic pathway and the organization of the crt gene cluster in R. sphaeroides as previously described (19) gain support from the earlier and elegant work of Armstrong et al (1). It has been known for some time that when R. sphaeroides is grown semiaerobically, it accumulates SO, a red pigment which is the end product of the Crt biosynthetic pathway in this bacterium (16). SE, a yellow carotenoid, is the penultimate product of this pathway and a biosynthetic precursor of SO.…”

supporting

confidence: 54%

Differential carotenoid composition of the B875 and B800-850 photosynthetic antenna complexes in Rhodobacter sphaeroides 2.4.1: involvement of spheroidene and spheroidenone in adaptation to changes in light intensity and oxygen availability

1996

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Rhodobacter sphaeroides 2.4.1 is a member of the nonsulfur purple facultative photosynthetic proteobacteria, capable of growth under a variety of cultivation conditions. In addition to the structural polypeptides and bacteriochlorophyll, the two major antenna complexes, B875 and B800-850, contain a variety of carotenoids which are an important structural and functional component of the membrane-bound photosynthetic complexes of this bacterium. Two major carotenoids, spheroidene and its keto derivative, spheroidenone, are differentially synthesized by R. sphaeroides, depending on the growth conditions. Spheroidene prevails during growth under anaerobic conditions and low light intensities, whereas spheroidenone is predominant in semiaerobically grown cells or during anaerobic growth at high light intensities. In this study, we demonstrate that in wild-type cells, spheroidene is predominantly associated with the B800-850 photosynthetic antenna complex and spheroidenone is more abundant in the B875 complex. Exploiting mutants defective in the biosynthesis of either the B875 or B800-850 light-harvesting complex, we demonstrate an association between the formation of either the B875 or B800-850 complex, on the one hand, and the accumulation of spheroidenone or spheroidene, on the other. The possible involvement of the conversion of spheroidene to spheroidenone as a significant control mechanism involved in the adaptation of R. sphaeroides to changes in light intensity and oxygen tension is discussed.

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supporting

confidence: 54%

Differential carotenoid composition of the B875 and B800-850 photosynthetic antenna complexes in Rhodobacter sphaeroides 2.4.1: involvement of spheroidene and spheroidenone in adaptation to changes in light intensity and oxygen availability

1996

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“…Several pathways of carotenoid biosynthesis in phototrophic bacteria have been described (Schmidt 1978). The spirilloxanthin family which is present in many of the species investigated, was first demonstrated in Rhodospirillum rubrum (Jensen et al 1958, Jensen et al 1961. The conversion of lycopene to spirilloxanthin involves hydroxylation, desaturation and methylation at both sides of the polyene chain.…”

mentioning

confidence: 99%

Carotenoid Profiles in Pigment-Protein Complexes of Rhodospirillum rubrum

Schwerzmann

Bachofen

1989

Plant and Cell Physiology

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Young cells of Rhodospirillum rubrum contain a set of carotenoids from lycopene to spirilloxanthin. During growth, intermediates are almost completely converted to spirilloxanthin. The ratio of the different carotenoid precursors vs. spirilloxanthin found in material of a certain age is the same in cells, chromatophores, light-harvesting complexes and reaction centers. Independent of the carotenoid composition and the age of the cells, the same detergent treatment can be used for isolation of pigment-protein complexes. Light-harvesting complexes of young cells containing mainly precursors of spirilloxanthin, as well as those of old cells in which spirilloxanthin dominates, both have their absorption maximum at 880 nm. It is thus assumed that all carotenoids of the spirilloxanthin series interact with bacteriochlorophyll a similarly to spirilloxanthin itself.From these results it is concluded that the micro-environment of these membrane-complexes is not influenced by the type of carotenoid present and that the assembly of the pigment-protein complexes in a growing membrane takes place before carotenoid biosynthesis has lead to the final product.

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“…In resting cells of R. rubrumz the carotenoids in the lycopene and P481 groups decreased during a 24 hour period with a concomitant increase in spirilloxanthin (6). The (7).…”

Section: Resultsmentioning

confidence: 99%