Bacterial schematic view

Figure 12.9 Schematic view of the bacterial-photosynthetic reaction centre and the energy transfers which occur. The groups are held in a fixed geometry by the surrounding proteins...

A schematic view of bacterial photosynthetic reaction centre with a chain of electron-carrying metal prosthetic groups is shown in Figure 11.4. The metal ions involved are magnesium (bacteriochlorophylls) and iron (haem and non-haem iron species). 

Figure 12.35. Cell Membranes of Prokaryotes. A schematic view of the membrane in bacterial cells surrounded by (A) two membranes or (B) one membrane.

Fig. 3. Schematic view of the bacterial RC. The M- and L-subunits of the RC are embedded in the membrane while the H- and the cytochrome-subunit are bound at the cytoplasmic and periplasmic side of the RC, respectively. The pathway of electron transfer is indicated by black dots. Q quinone, HQH quinol.

In 1984, Deisenhofer and colleagues reported an X-ray structure of the RC of the photosynthetic bacterium Rhodopseudomonas viridisJ- As explained in subsequent review articles, -" the real tour de force of the work was their attempt to crystallize the membrane protein. The magnificent crystallographic work which led to the structure is of course equally important. This structure determination can no doubt be regarded as a major scientific event not only because of its direct link to bacterial photosynthesis but also for the many studies which it inspired in various fields of research, from biology to biophysics and chemistry. Figure 2 shows a schematic view of the photosynthetic RC from Rhodopseudomonas viridis, with its special pair (SP) of bacteriochlorophylls, its two accessory bacteriochlorophylls (BCh), and the two bacteriopheophytins (BPh). Above the special pair, a tetraheme cytochrome also plays an important role. 

Figure 17.2 (a) Schematic showing the synthesis mechanism of cellulose hy acetohacter xylinum at the cell surface showing the different hierarchical stages involved (h) enlarged view of the cellulose synthesizing sites that are present on the bacterial surface. 

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