scholarly journals A Photosynthesis-Specific Rubredoxin-Like Protein Is Required for Efficient Association of the D1 and D2 Proteins during the Initial Steps of Photosystem II Assembly

2019 ◽  
Vol 31 (9) ◽  
pp. 2241-2258 ◽  
Author(s):  
Éva Kiss ◽  
Jana Knoppová ◽  
Guillem Pascual Aznar ◽  
Jan Pilný ◽  
Jianfeng Yu ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
D1 And D2 Proteins

scholarly journals Amino acid oxidation of the D1 and D2 proteins by oxygen radicals during photoinhibition of Photosystem II

2017 ◽  
Vol 114 (11) ◽  
pp. 2988-2993 ◽  
Author(s):  
Ravindra Kale ◽  
Annette E. Hebert ◽  
Laurie K. Frankel ◽  
Larry Sallans ◽  
Terry M. Bricker ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Amino Acid ◽  
Photosystem Ii ◽  
Light Stress ◽  
Reactive Oxygen ◽  
Nonheme Iron ◽  
Oxidative Modification ◽  
Oxygen Species ◽  
Oxidatively Modified ◽  
D1 And D2 Proteins

The Photosystem II reaction center is vulnerable to photoinhibition. The D1 and D2 proteins, lying at the core of the photosystem, are susceptible to oxidative modification by reactive oxygen species that are formed by the photosystem during illumination. Using spin probes and EPR spectroscopy, we have determined that both O2•− and HO• are involved in the photoinhibitory process. Using tandem mass spectroscopy, we have identified a number of oxidatively modified D1 and D2 residues. Our analysis indicates that these oxidative modifications are associated with formation of HO• at both the Mn4O5Ca cluster and the nonheme iron. Additionally, O2•− appears to be formed by the reduction of O2 at either PheoD1 or QA. Early oxidation of D1:332H, which is coordinated with the Mn1 of the Mn4O5Ca cluster, appears to initiate a cascade of oxidative events that lead to the oxidative modification of numerous residues in the C termini of the D1 and D2 proteins on the donor side of the photosystem. Oxidation of D2:244Y, which is a bicarbonate ligand for the nonheme iron, induces the propagation of oxidative reactions in residues of the D-de loop of the D2 protein on the electron acceptor side of the photosystem. Finally, D1:130E and D2:246M are oxidatively modified by O2•− formed by the reduction of O2 either by PheoD1•− or QA•−. The identification of specific amino acid residues oxidized by reactive oxygen species provides insights into the mechanism of damage to the D1 and D2 proteins under light stress.

scholarly journals Function of two β-carotenes near the D1 and D2 proteins in photosystem II dimers

2007 ◽  
Vol 1767 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Hiroshi Ishikita ◽  
Bernhard Loll ◽  
Jacek Biesiadka ◽  
Jan Kern ◽  
Klaus-Dieter Irrgang ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
D1 And D2 Proteins

scholarly journals Tocopherol controls D1 amino acid oxidation by oxygen radicals in Photosystem II

2021 ◽  
Vol 118 (4) ◽  
pp. e2019246118
Author(s):  
Aditya Kumar ◽  
Ankush Prasad ◽  
Michaela Sedlářová ◽  
Ravindra Kale ◽  
Laurie K. Frankel ◽  
...  
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Nonheme Iron ◽  
Oxidative Modification ◽  
Oxygenic Photosynthesis ◽  
Acid Oxidation ◽  
Membrane Protein Complex ◽  
Oxidative Modifications ◽  
Tocopherol Cyclase ◽  
D1 And D2 Proteins

Photosystem II (PSII) is an intrinsic membrane protein complex that functions as a light-driven water:plastoquinone oxidoreductase in oxygenic photosynthesis. Electron transport in PSII is associated with formation of reactive oxygen species (ROS) responsible for oxidative modifications of PSII proteins. In this study, oxidative modifications of the D1 and D2 proteins by the superoxide anion (O2•−) and the hydroxyl (HO•) radicals were studied in WT and a tocopherol cyclase (vte1) mutant, which is deficient in the lipid-soluble antioxidant α-tocopherol. In the absence of this antioxidant, high-resolution tandem mass spectrometry was used to identify oxidation of D1:130E to hydroxyglutamic acid by O2•− at the PheoD1 site. Additionally, D1:246Y was modified to either tyrosine hydroperoxide or dihydroxyphenylalanine by O2•− and HO•, respectively, in the vicinity of the nonheme iron. We propose that α-tocopherol is localized near PheoD1 and the nonheme iron, with its chromanol head exposed to the lipid–water interface. This helps to prevent oxidative modification of the amino acid’s hydrogen that is bonded to PheoD1 and the nonheme iron (via bicarbonate), and thus protects electron transport in PSII from ROS damage.

Characterization of photosystem II with the atomic-force microscope

1992 ◽  
Vol 50 (2) ◽  
pp. 1146-1147
Author(s):  
Kathleen M. Marr ◽  
Mary K. Lyon
Keyword(s):  
Photosystem Ii ◽  
Atomic Force Microscope ◽  
Three Dimensional ◽  
Biologically Active ◽  
Atomic Force ◽  
Freeze Etching ◽  
Image Averaging ◽  
Oxygen Evolving ◽  
Averaging Techniques

Photosystem II (PSII) is different from all other reaction centers in that it splits water to evolve oxygen and hydrogen ions. This unique ability to evolve oxygen is partly due to three oxygen evolving polypeptides (OEPs) associated with the PSII complex. Freeze etching on grana derived insideout membranes revealed that the OEPs contribute to the observed tetrameric nature of the PSIl particle; when the OEPs are removed, a distinct dimer emerges. Thus, the surface of the PSII complex changes dramatically upon removal of these polypeptides. The atomic force microscope (AFM) is ideal for examining surface topography. The instrument provides a topographical view of individual PSII complexes, giving relatively high resolution three-dimensional information without image averaging techniques. In addition, the use of a fluid cell allows a biologically active sample to be maintained under fully hydrated and physiologically buffered conditions. The OEPs associated with PSII may be sequentially removed, thereby changing the surface of the complex by one polypeptide at a time.

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