Phylogenetic Analysis of Photosynthetic Reaction Centers of Purple Bacteria and Green Filamentous Bacteria

1995 ◽  
pp. 975-978 ◽  
Author(s):  
Kenji V. P. Nagashima ◽  
Satoshi Hanada ◽  
Akira Hiraishi ◽  
Keizo Shimada ◽  
Katsumi Matsuura
Keyword(s):  
Phylogenetic Analysis ◽  
Purple Bacteria ◽  
Reaction Centers ◽  
Photosynthetic Reaction Centers ◽  
Filamentous Bacteria

scholarly journals Structural Basis of Cyanobacterial Photosystem II Inhibition by the Herbicide Terbutryn

2011 ◽  
Vol 286 (18) ◽  
pp. 15964-15972 ◽  
Author(s):  
Matthias Broser ◽  
Carina Glöckner ◽  
Azat Gabdulkhakov ◽  
Albert Guskov ◽  
Joachim Buchta ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Photosystem Ii ◽  
Purple Bacteria ◽  
Chloride Ion ◽  
Reaction Centers ◽  
Structural Basis ◽  
Photosynthetic Reaction Centers ◽  
Thermophilic Cyanobacterium ◽  
Herbicide Binding ◽  
Water Oxidizing Complex

Herbicides that target photosystem II (PSII) compete with the native electron acceptor plastoquinone for binding at the QB site in the D1 subunit and thus block the electron transfer from QA to QB. Here, we present the first crystal structure of PSII with a bound herbicide at a resolution of 3.2 Å. The crystallized PSII core complexes were isolated from the thermophilic cyanobacterium Thermosynechococcus elongatus. The used herbicide terbutryn is found to bind via at least two hydrogen bonds to the QB site similar to photosynthetic reaction centers in anoxygenic purple bacteria. Herbicide binding to PSII is also discussed regarding the influence on the redox potential of QA, which is known to affect photoinhibition. We further identified a second and novel chloride position close to the water-oxidizing complex and in the vicinity of the chloride ion reported earlier (Guskov, A., Kern, J., Gabdulkhakov, A., Broser, M., Zouni, A., and Saenger, W. (2009) Nat. Struct. Mol. Biol. 16, 334–342). This discovery is discussed in the context of proton transfer to the lumen.

scholarly journals Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers

2020 ◽  
Vol 117 (28) ◽  
pp. 16373-16382 ◽  
Author(s):  
Hiroyuki Tamura ◽  
Keisuke Saito ◽  
Hiroshi Ishikita
Keyword(s):  
Excitation Energy ◽  
Water Splitting ◽  
Charge Separation ◽  
Purple Bacteria ◽  
D1 Protein ◽  
Reaction Centers ◽  
Electronic Coupling ◽  
Separation Mechanism ◽  
Photosynthetic Reaction Centers ◽  
Charged Residues

In photosynthetic reaction centers from purple bacteria (PbRC) and the water-oxidizing enzyme, photosystem II (PSII), charge separation occurs along one of the two symmetrical electron-transfer branches. Here we report the microscopic origin of the unidirectional charge separation, fully considering electron–hole interaction, electronic coupling of the pigments, and electrostatic interaction with the polarizable entire protein environments. The electronic coupling between the pair of bacteriochlorophylls is large in PbRC, forming a delocalized excited state with the lowest excitation energy (i.e., the special pair). The charge-separated state in the active branch is stabilized by uncharged polar residues in the transmembrane region and charged residues on the cytochromec2binding surface. In contrast, the accessory chlorophyll in the D1 protein (ChlD1) has the lowest excitation energy in PSII. The charge-separated state involves ChlD1•+and is stabilized predominantly by charged residues near the Mn4CaO5cluster and the proceeding proton-transfer pathway. It seems likely that the acquirement of water-splitting ability makes ChlD1the initial electron donor in PSII.

scholarly journals Structures and functions of carotenoids bound to reaction centers from purple photosynthetic bacteria

2006 ◽  
Vol 78 (8) ◽  
pp. 1505-1518 ◽  
Author(s):  
Hideki Hashimoto ◽  
Ritsuko Fujii ◽  
Kazuhiro Yanagi ◽  
Toshiyuki Kusumoto ◽  
Alastair T. Gardiner ◽  
...  
Keyword(s):  
Electrostatic Field ◽  
Flash Photolysis ◽  
Purple Bacteria ◽  
Reaction Centers ◽  
Photosynthetic Reaction Centers ◽  
Triplet Energy ◽  
X Ray ◽  
X Ray Crystallography ◽  
Purple Photosynthetic Bacteria ◽  
Value Decomposition

The photoprotective function of 15,15'-cis-carotenoids bound to the photosynthetic reaction centers (RCs) of purple bacteria has been studied using carotenoids reconstituted into carotenoidless RCs from Rhodobacter sphaeroides strain R26.1. The triplet-energy level of the carotenoid has been proposed to affect the quenching of the triplet state of special-pair bacteriochlorophyll (P). This was investigated using microsecond flash photolysis to detect the carotenoid triplets as a function of the number of conjugated double bonds, n. The carotenoid triplet signals were extracted by using singular-value decomposition (SVD) of the huge matrices data, and were confirmed for those having n = 8 to 11. This interpretation assumes that the reconstituted carotenoids occupy the same binding site in the RC. We have been able to confirm this assumption using X-ray crystallography to determine the structures of carotenoidless, wild-type carotenoid-containing, and 3,4-dihydro-spheroidene-reconstituted RCs. The X-ray study also emphasized the importance of the methoxy group of the carotenoids for binding to the RCs. Electroabsorption (Stark) spectroscopy was used to investigate the effect of the carotenoid on the electrostatic field around P. This electrostatic field changed by 10 % in the presence of the carotenoid.

Horizontal transfer of genes coding for the photosynthetic reaction centers of purple bacteria

1997 ◽  
Vol 45 (2) ◽  
pp. 131-136 ◽  
Author(s):  
Kenji V. P. Nagashima ◽  
Akira Hiraishi ◽  
Keizo Shimada ◽  
Katsumi Matsuura
Keyword(s):  
Horizontal Transfer ◽  
Purple Bacteria ◽  
Reaction Centers ◽  
Photosynthetic Reaction Centers
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