Chlorobactene

MQ. oxoMQ, Cyts b and c BChl a. BChl c, d or e Plasma membrane chlorosome Chlorobactene, isorenieratene, 7-carotenc... 

Chlorobactane (28) Chlorobactene (27) hydroxychlorobactene Green pigmented Chlorobiaceae Grice et al. (1998c)... 

The Chlorobiaceae have the isorenieratene pathway only and can be divided the isorenieratene and the chlorobactene pathways (Tables 1 and 6). The species which mainly contain isorenieratene always have BChl c or 4 as major component, and those which chlorobactene always have BChl e (Imhoff, 1995). Chi. tepidum contains additional carotenoid glucoside esters. Mostly the carotenes are located in chloro-somes, accompanied by BChl c, while carotenoid glucoside esters are mainly located in the membranes... 

TNO Chlorobactene 0-FA y-carotenc (24), dihydro-y-carotene (22), OH-y-carotene (2), chlorobactene (20), dihydrochlorobactene (23), OH-chlorobactene (2), OH-y-carotene glucoside ester (5), OH-chlorobactene glucoside ester (3) 5... 

Takaichi S, Wang Z-Y, Umetsu M, Nozawa T, Shimada K and Madigan MT (1997a) New carotenoids from the thermophilic green sulfur bacterium Chlorobium tepidum r,2 -dihydro-y-carotene, l, 2 -dihydrochlorobactene, and OH-chlorobactene glucoside ester, and the carotenoid composition of different strains. Arch Microbiol 168 270-276... 

Fig. /(5. H PLC elution profiles of (a) spheroidene extracted from the RC of Rb. sphaeroides 2.4.1 (acetone extract, detection at 450 nm), (b) / -carotene extracted from the PS II RC of spinach (acetone extract, detection at 450 nm), (c) y-carotene and chlorobactene extracted from the RC of Ch. tepidum (DMF extract, detection at 460 nm), and (d) )5-carotene extracted from the PS I RC of Sc. vulcanus (acetone extract, detection at 450 nm).

Fig. 17.15-C(s-carotenoids identified so far in the RCs of various photosynthetic organisms (a) neurosporene, (b) spheroidene and (c) spirilloxanthin in the quinone-type RC of puiple non-sulfur bacteria, Rb. sphaeroides QIC, 2.4.1 and Rs. rubrum SI (d) y-carotene and (e) chlorobactene in the iron sulfiir-type RC of green sulfur bacterium, Cb. tepidum-, and (f) Carotene in the quinone-type PS II RC of spinach chioropiasts as well as in the iron sulfur-type PS I RC of a cyanobacterium. Sc. vulcanus, and spinach chioropiasts.

Chlorobactene (105) biosynthesis involves a methyl migration. A preliminary report suggests that the migrating methyl group is not labelled by [2- C]-mevalonate. Zeaxanthin (106) biosynthesis in a Flavobacterium species involves, as expected, the loss of the two tritium atoms from [2- " C,3R,5R- H]mevalonic... 

Green sulfur bacteria produce some types of carotenoids, p-carotene 13, chlorobactene 46, and their derivatives including their glucoside, and/or isorenieratene 50 (Fig. 106.6) [5, 14]. 

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