Cyanobacteria sulfur

H2S- S-S20i- ->SO ) bacteria, some cyanobacteria Chemoautotrophic sulfur oxidizers... 

Aside from C. vinosum, type III-PHA synthases have so far been detected exclusively in the phototrophic purple sulfur bacteria such as Thiocystis viol-acea [51] and Thiocapsa pfennigii [26, 57] and in cyanobacteria such as Synechocystis sp. PCC6803 [49] or Synechococcus sp. MAI 9 [58]. In contrast, the photosynthetic nonsulfur purple bacteria possess type I-PHA synthases. 

Biesiadka, J., Loll, B., Kern, J., Irrgang K/D. and Zouni, A. (2004). Crystal structure of cyanobacteria photosystem II at 3.2A resolution. Phys. Chem. Chem. Phys., 6, 4733-4736 Canfield, D.E., Habicht, K.S. and Thamdrup, B. (2000). The Achaean sulfur cycle and the early history of atmospheric oxygen. Science, 288, 658-661... 

Prokaryote heterotrophs precursors of cyanobacteria. Stromatolites. Sulfur bacteria Beginning of photosynthesis Traces... 

Figure 10.3 Z-scheme of oxygenic photosynthesis in green algae and cyanobacteria, showing links to hydrogenase. Q (plastoquinone) and X (an iron-sulfur cluster) are electron acceptors from photosystems II and I, respectively.The two hydrogenases shown are the NADP-dependent bidirectional hydrogenase and a ferredoxin-dependent enzyme.

The biological classification schemes for bacteria and archaea are still being developed because of the rapid pace of new discoveries in genomics. The two most important phyla of marine bacteria are the cyanobacteria, which are photosynthetic, and the proteobacteria. The latter include some photosynthetic species, such as the purple photosynthetic bacteria and N2 fixers. Other members of this diverse phylum are the methanotrophs, nitrifiers, hydrogen, sulfur and iron oxidizers, sulfete and sulfur reducers, and various bioluminescent species. 

Purple and green sulfur bact. (Chromatium, Chiorobiuni), Cyanobacteria... 

Photosynthetic bacteria have relatively simple phototransduction machinery, with one of two general types of reaction center. One type (found in purple bacteria) passes electrons through pheophytin (chlorophyll lacking the central Mg2+ ion) to a quinone. The other (in green sulfur bacteria) passes electrons through a quinone to an iron-sulfur center. Cyanobacteria and plants have two photosystems (PSI, PSII), one of each type, acting in tandem. Biochemical and biophysical... 

These two reaction centers in plants act in tandem to catalyze the light-driven movement of electrons from HaO to NADP+ (Fig. 19-49). Electrons are carried between the two photosystems by the soluble protein plastocyanin, a one-electron carrier functionally similar to cytochrome c of mitochondria. To replace the electrons that move from PSII through PSI to NADP+, cyanobacteria and plants oxidize H20 (as green sulfur... 

If an enzyme binds a flavin radical much more tightly than the fully oxidized or reduced forms, reduction of the flavoprotein will take place in two one-electron steps. In such proteins the values of E° for the two steps may be widely separated. The best known examples are the small, low-potential electron-carrying proteins known as flavodoxins.266 269a These proteins, which carry electrons between pairs of other redox proteins, have a variety of functions in anaerobic and photosynthetic bacteria, cyanobacteria, and green algae. Their functions are similar to those of the ferredoxins, iron-sulfur proteins that are considered in Chapter 16. 

In contrast, the reaction centers of green sulfur bacteria resemble PSI of chloroplasts. Their reaction centers also receive electrons from a reduced quinone via a cytochrome be complex.245 However, the reduced form of the reaction center bacteriochlorophyll donates electrons to iron-sulfur proteins as in PSI (Fig. 23-17). The latter can reduce a quinone to provide cyclic photophosphorylation. Cyanobacteria have a photosynthetic apparatus very similar to that of green algae and higher plants. 

Rhodopseudomonas viridis (now Blasatochloris) Green plants and Cyanobacteria Green sulfur bacteria, heliobacteriaa... 

Fig. 3 Schematic model of light-harvesting compartments in photosynthetic organisms and their position with respect to the membrane and the reaction centers. RC1(2) Photosystem I(II) reaction centre. Peripheral membrane antennas Chlorosome/FMO in green sulfur and nonsulfur bacteria, phycobilisome (PBS) in cyanobacteria and rhodophytes and peridinin-chlorophyll proteins (PCP) in dyno-phytes. Integral membrane accessory antennas LH2 in purple bacteria, LHC family in all eukaryotes. Integral membrane core antennas B808-867 complex in green nonsulfur bacteria, LH1 in purple bacteria, CP43/CP47 (not shown) in cyanobacteria and all eukaryotes.

The increase of PolyP accumulation in cyanobacteria was observed under conditions of sulfur deficiency, which diminished the growth (Lawry and Jensen, 1979 1986). This... 

PS I from cyanobacteria consist of 11 protein subunits and several cofactors. After the photoexcitation of the primary donor, a dimer of chlorophyll a (Chla)2, P700, an electron is transferred via a chlorophyll (A0) to aphylloquinone (AO and then to the iron sulfur clusters, Fx, FAand FB. (Witt, 1996 Itoh et al., 2000)). 

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