Rhodospirillum rubrum preparation

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-... 

The Mg2+-activated ATPase (or ATP synthase) is made up of two parts. The Fj component is the catalytic, Mg2+-binding, extrinsic membrane protein composed of five different subunits, a, (3, y, S and e. The F0 component is an intrinsic membrane complex that contains three subunits, a, b and c, and mediates proton translocation. The F, protein is bound to the membrane through interaction with F0. The complexity of the F,F0 enzyme has presented many difficulties. Hie greatest advances have been made for the bacterial enzymes, notably for thermophiles, Escherichia coli and Rhodospirillum rubrum, where progress has been made in the purification of subunits and their reconstitution into membranes, and the identification of binding sites for Mg2+ and nucleotides on the Fi subunits.300 FiF0 preparations can be incorporated into liposomes and display H+ translocation, ATP-P, exchange and ATP synthesis.301... 

The genes for the catalytic part of the F F -ATPase from two different phototrophic bacteria have been sequenced Rhodospirillum rubrum (1) and Rhodopseudomonas blastica (2). The sequence of the genes for the F of R. rubrum is also known (3). The atp1-operon of the latter bacteria encodes the five subunits found in the preparations of the enzyme (Walker, J. E., Falk, G., and Strid, A., unpublished results) as judged by N-terminaT analysis. The atp-operon of Rps. blastica also contains a sixth gene, termed X. The F--protein has not previously been prepared from Rps. blas-tica. Some characteristic properties of a pure preparation of the enzyme is compared to the properties of the R. rubrum F. ... 

Laser-microwave spectroscopy was also reported of the triplet state of photosynthetic bacteria, namely, of Rhodospirillum rubrum, Rhodo-pseudomonas spheroides, and Chromaticum vinosum, in chemically reduced cellular preparations at 2 K. The authors found similarities of the triplet state frequencies, spectral features, and intersystem crossing rates that suggest that the reaction centers in photosynthetic bacteria possess a common structure. 

Studies of the sequence changes in cytodirome c found in 30 species ranging from man through moth to castor bean show that the hydrophobic nature of the haem box is conserved. A number of residues on the left side including the aromatics Tyr-59,1 -67, and Tyr-74 are conserved, which is consistent with the importance of this part of the molecule to electron transfer. The character of the basic region is also conserved, which explains the observation that cytochrome c from one species will react in vitro with cytochrome-oxidase preparations from distantly related species. Modelbuilding studies on bacterial cytochromes show that the sequence of cytochrome C from Rhodospirillum rubrum with 114 amino-acids can be easily... 

Several bacterial species were used for preparing RCs and/or chromatophores Rhodobacter sphaeroides strains R26 and 2-4-1, Rhodospirillum rubrum strain G9. Light-... 

We have isolated reaction centers from Rhodospirillum rubrum G- 9 cells labeled with the isotope 39-Fe. On LDS-polyacrylamide electrophoresis the preparation shows the typical three bands H, M and L and some minor contaminations (Figure 1). The specific staining technique for c-type cytochromes gave no positive reaction, indicating that there is no such cytochrome among the contaminations (datanot shown). 

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