Chlorobium chlorophyll

The phytyl group it is replaced by Cj5 famesyl or olher. pol3 renyl group in Chlorobium chlorophyll... 

Position 2 in chlorobium chlorophyll 660 is presumed to contain a hydroxy ethyl group, CH3CHOH—. These are designated as protons 2 and 2. ... 

The green sulfur bacteria are the "classical" green bacteria. They contain relatively large amounts of chlorobium chlorophyll (bacteriochlorophyll c, d or e), in addition to BChl a. The latter pigment is mainly contained in the cytoplasmic membrane, whereas most of the BChl c is situated in the chlorosomes, oblong bodies of several hundred A diameter that are bound to the cytoplasmic membrane. Green sulfur bacteria are strict anaerobes which are found in fresh water as well as in marine habitats. 

Figure 23-28 (A) Model of a light-harvesting chlorosome from green photosynthetic sulfur bacteria such as Chlorobium tepidum and species of Prosthecochloris. The chlorosome is attached to the cytoplasmic membrane via a baseplate, which contains the additional antenna bacteriochlorophylls (795 BChl a) and is adjacent to the trimeric BChl protein shown in (B) and near the reaction center. After Li et al.302 and Remigy et a/.304 (B) Alpha carbon diagram of the polypeptide backbone and seven bound BChl a molecules in one subunit of the trimeric protein from the green photosynthetic bacterium Prosthecochloris. For clarity, the magnesium atoms, the chlorophyll ring substituents, and the phytyl chains, except for the first bond, are omitted. The direction of view is from the three-fold axis, which is horizontal, toward the exterior of the molecule. From Fenna and Matthews.305 See also Li et al.302...

All species contain two different chlorophylls, BChl a and an additional light-harvesting pigment, either BChl c, d ox e [40], As in Chloroflexus these light-harvesting pigments are housed in chlorosomes located adjacent to the cytoplasmic membrane [45,46]. In Chlorobium BChl c is associated with a 7.5-kDa polypeptide. (J.M. Olson and P. Roepstorff, unpublished). A small amount of energytransferring BChl a is also found in the chlorosomes [47,48], but most of the BChl a is found in a water-soluble protein associated with the cytoplasmic membrane [45]. The RC (see Fig. 4 and Ref. 36) is similar to that of PS I in cyanobacteria and chloroplasts. The primary electron donor P-840 = +0.25 V) is a BChl... 

C Griesbeck, C Flager-Braun, FI RogI and G Flauska (1998) Quantitation of P840 reaction center preparations from Chlorobium tepidum Chlorophylls and FMO-protein. Biochim Biophys Acta 1365 285-293... 

We have recently obtained neutron diffraction data on Chlorobium pheophytins [26] that provide the first high resolution hydrogen bonding results for chlorophyll derivatives and serve as calibration for both the ENDOR and FTIR results discussed above. 

It is possible, however, within certain limits at least, depending on the unsaturation degree of the oil, to obtain from it by mere solvent crystallization (i.e., acetone, ethyl acetate) the oil s NGC ftaction, thus avoiding saponification (Jacini and Fedeli, 1967). Obviously, it is possible to apply to the thus enriched fraction the aforementioned separation methods already employed with tissue lipids. By such techniques, it has recently been possible to evaluate the amount of terpene alcohols and of sterols present in the free or ester-ified form, bringing into evidence some points which have previously not been noticed. In olive oil, for instance, the fatty acids present in terpenic alcohol and sterol esters are remarkably different from those of the oil itself, because of the presence of more than 9% of a C20 acid practically absent in the glycerides of the oil itself. In olive oil the presence has been observed of a chlorophyll different from the a and b and probably identical to that isolated from chlorobium (Stanier and Smith, 1960 Jacini and Fedeli, 1967). 

Agostiano, A., Catucci, L., Colafemmina, G., deUa Monica, M., and Scheer, H., Relevance of the phytyl chain of the chlorophylls on the lamellar phase formation and organization, Biophys.J., 84,189, 2000. Van Rossum, B.-J., Steensgaard, D.B., Mulder, EM., Boender, G.J., Schaffner, K., Holzwarth, A.R., and de Groot, H.J.M., A refined model of the chlorosomal antennae of the green bacterium Chlorobium tepidum from proton chemical shift constraints obtained with high-field two-dimensional and three-dimensional MAS NMR dipolar correlation. Biochemistry, 40, 1587, 2001. Hynninen, RH., Chemistry of chlorophylls modifications, in Chlorophylls, Scheer, H., Ed., CRC Press LLC, Boca Raton, FL, 1991, p. 145. 

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