Sulfolipid structure

As an example of an asymmetric membrane integrated protein, the ATP synthetase complex (ATPase from Rhodospirillum Rubrum) was incorporated in liposomes of the polymerizable sulfolipid (22)24). The protein consists of a hydrophobic membrane integrated part (F0) and a water soluble moiety (Ft) carrying the catalytic site of the enzyme. The isolated ATP synthetase complex is almost completely inactive. Activity is substantially increased in the presence of a variety of amphiphiles, such as natural phospholipids and detergents. The presence of a bilayer structure is not a necessary condition for enhanced activity. Using soybean lecithin or diacetylenic sulfolipid (22) the maximal enzymatic activity is obtained at 500 lipid molecules/enzyme molecule. With soybean lecithin, the ATPase activity is increased 8-fold compared to a 5-fold increase in the presence of (22). There is a remarkable difference in ATPase activity depending on the liposome preparation technique (Fig. 41). If ATPase is incorporated in-... 

Ciminiello P, Dell Aversano C, Fattorusso E, Forino M, Magno S, Di Rosa M, Ianaro A, Poletti R (2002) Structure and Stereochemistry of a New Cytotoxic Polychlorinated Sulfolipid from Adriatic Shellfish. J Am Chem Soc 124 13114... 

Mayers and Haines (1967) have isolated a sulfolipid, 1,14-docosyl disulfate, from the phytoflagellate, Ochromonas danica. Acid hydrolysis of the sulfatide yielded a diol. The structures of the sulfatide (lipoid sulfate ester) and the diol were determined by infrared, NMR, and mass spectroscopy. The infrared spectrum of the sulfatide diol had bands indicative of a long-chain diol 1060cm (primary alcohol CO), 1120 (secondary alcohol CO), and 718 cm (long-chain aliphatic CH2rocking). 

Fig. 3. Structures of the sulfolipids of O. danica. In addition to the structures indicated two trichloro derivatives, two tetracholoro derivatives, and another pentachloro derivative of doco-sane 1,14-disulfate and a dichloro derivative of tetracosane l,lS-di uIfate have been reported but not characterized (Haines, 1973b). Bromosulfatides of similar stucture also exist.

While the first mention of a sulfolipid in brain tissue was in 1884 (Thudichum), definitive studies on the structure of cerebroside sulfates are still in progress (Yamakawa et al. 1962 Stoffyn and Stoffyn 1963 Taketomi and Yamakawa 1964). Similarly, the metabolism of cerebroside sulfates is largely unknown. Brain... 

Cauliflower bud plastids have not yet been investigated for their ability to form FG, the major plastid phospholipid, and SL, another unique plastid constituent. It is likely that results similar to those obtained with mature spinach chloroplasts would be obtained. Indeed, plastids are able to synthesize their major constituents (galactolipids, sulfolipid, PG) as far as they contain the so-called prokaryotic structure. ... 

Ciminiello, P., Dell Aversano, C., Eattorusso, E., Eorino, M., Magno, S., Di Rosa, M., lanaro, A., and Poletti, R. (2002a) Structure and stereochemistry of a new cytotoxic polychlorinated sulfolipid from Adriatic shellfish./. Am. Chem, Soc, 124, 13114—13120. 

In the previous discussion it was suggested that membrane integration of intrinsic proteins could be facilitated by the interaction of hydrophobic regions of the nascent peptides with the phospholipids of the bilayer. Although it is assumed that the basic structure of the bilayer is the same for all membranes, the lipid compositions of various membranes show significant differences, both with respect to the relative proportions of the various phospholipids and their fatty substituents. In addition, some membranes may contain special types of lipids (sterols, sulfolipids, cardiolipin, etc.) that are absent in other membranes. It is also conceivable that there may exist regional differences in lipid composition within a single membrane. 

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