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 Viewing oxidative stress through the lens of oxidative signalling rather than damage

2017 ◽  
Vol 474 (6) ◽  
pp. 877-883 ◽  
Author(s):  
Christine H. Foyer ◽  
Alexander V. Ruban ◽  
Graham Noctor
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Photosystem Ii ◽  
Oxidative Damage ◽  
Reactive Oxygen ◽  
Oxidative Modification ◽  
Current View ◽  
Oxygen Species ◽  
Repair Processes

Concepts of the roles of reactive oxygen species (ROS) in plants and animals have shifted in recent years from focusing on oxidative damage effects to the current view of ROS as universal signalling metabolites. Rather than having two opposing activities, i.e. damage and signalling, the emerging concept is that all types of oxidative modification/damage are involved in signalling, not least in the induction of repair processes. Examining the multifaceted roles of ROS as crucial cellular signals, we highlight as an example the loss of photosystem II function called photoinhibition, where photoprotection has classically been conflated with oxidative damage.

Rescue of anaemia and autoimmune responses in SOD1-deficient mice by transgenic expression of human SOD1 in erythrocytes

2009 ◽  
Vol 422 (2) ◽  
pp. 313-320 ◽  
Author(s):  
Yoshihito Iuchi ◽  
Futoshi Okada ◽  
Rina Takamiya ◽  
Noriko Kibe ◽  
Satoshi Tsunoda ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Energy Charge ◽  
Reactive Oxygen ◽  
Oxidative Modification ◽  
Autoimmune Response ◽  
Oxygen Species ◽  
Autoantibody Production ◽  
Deficient Mice ◽  
Human Sod1

Oxidative stress has been implicated as a cause of various diseases such as anaemia. We found that the SOD1 [Cu,Zn-SOD (superoxide dismutase)] gene deficiency causes anaemia, the production of autoantibodies against RBCs (red blood cells) and renal damage. In the present study, to further understand the role of oxidative stress in the autoimmune response triggered by SOD1 deficiency, we generated mice that had the hSOD1 (human SOD1) transgene under regulation of the GATA-1 promoter, and bred the transgene onto the SOD1−/− background (SOD1−/−;hSOD1tg/+). The lifespan of RBCs, levels of intracellular reactive oxygen species, and RBC content in SOD1−/−;hSOD1tg/+ mice, were approximately equivalent to those of SOD1+/+ mice. The production of antibodies against lipid peroxidation products, 4-hydroxy-2-nonenal and acrolein, as well as autoantibodies against RBCs and carbonic anhydrase II were elevated in the SOD1−/− mice, but were suppressed in the SOD1−/−;hSOD1tg/+ mice. Renal function, as judged by blood urea nitrogen, was improved in the transgenic mice. These results rule out the involvement of a defective immune system in the autoimmune response of SOD1-deficient mice, because SOD1−/−;hSOD1tg/+ mice carry the hSOD1 protein only in RBCs. Metabolomic analysis indicated a shift in glucose metabolism to the pentose phosphate pathway and a decrease in the energy charge potential of RBCs in SOD1-deficient mice. We conclude that the increase in reactive oxygen species due to SOD1 deficiency accelerates RBC destruction by affecting carbon metabolism and increasing oxidative modification of lipids and proteins. The resulting oxidation products are antigenic and, consequently, trigger autoantibody production, leading to autoimmune responses.

scholarly journals Arginine Biosynthesis Modulates Pyoverdine Production and Release in Pseudomonas putida as Part of the Mechanism of Adaptation to Oxidative Stress

2019 ◽  
Vol 201 (22) ◽  
Author(s):  
Laura Barrientos-Moreno ◽  
María Antonia Molina-Henares ◽  
Marta Pastor-García ◽  
María Isabel Ramos-González ◽  
Manuel Espinosa-Urgel
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Amino Acid ◽  
Pseudomonas Putida ◽  
Reactive Oxygen ◽  
Full Detail ◽  
Oxygen Species ◽  
Arginine Biosynthesis ◽  
Content Type ◽  
And Oxidative Stress

ABSTRACT Iron is essential for most life forms. Under iron-limiting conditions, many bacteria produce and release siderophores—molecules with high affinity for iron—which are then transported into the cell in their iron-bound form, allowing incorporation of the metal into a wide range of cellular processes. However, free iron can also be a source of reactive oxygen species that cause DNA, protein, and lipid damage. Not surprisingly, iron capture is finely regulated and linked to oxidative-stress responses. Here, we provide evidence indicating that in the plant-beneficial bacterium Pseudomonas putida KT2440, the amino acid l-arginine is a metabolic connector between iron capture and oxidative stress. Mutants defective in arginine biosynthesis show reduced production and release of the siderophore pyoverdine and altered expression of certain pyoverdine-related genes, resulting in higher sensitivity to iron limitation. Although the amino acid is not part of the siderophore side chain, addition of exogenous l-arginine restores pyoverdine release in the mutants, and increased pyoverdine production is observed in the presence of polyamines (agmatine and spermidine), of which arginine is a precursor. Spermidine also has a protective role against hydrogen peroxide in P. putida, whereas defects in arginine and pyoverdine synthesis result in increased production of reactive oxygen species. IMPORTANCE The results of this study show a previously unidentified connection between arginine metabolism, siderophore turnover, and oxidative stress in Pseudomonas putida. Although the precise molecular mechanisms involved have yet to be characterized in full detail, our data are consistent with a model in which arginine biosynthesis and the derived pathway leading to polyamine production function as a homeostasis mechanism that helps maintain the balance between iron uptake and oxidative-stress response systems.

scholarly journals Susceptibilities of lactoferrin and transferrin to myeloperoxidase-dependent loss of iron-binding capacity

1988 ◽  
Vol 250 (2) ◽  
pp. 613-616 ◽  
Author(s):  
C C Winterbourn ◽  
A L Molloy
Keyword(s):  
Reactive Oxygen Species ◽  
Binding Capacity ◽  
Reactive Oxygen ◽  
Oxidative Modification ◽  
Iron Binding ◽  
Oxygen Species ◽  
Protective Groups ◽  
The Difference ◽  
Iron Binding Capacity

Apolactoferrin and apotransferrin lost their ability to subsequently bind iron when exposed to an excess of either HOCl or myeloperoxidase plus H2O2 and Cl-. Apolactoferrin, however, was more resistant than apotransferrin. By oxidizing a mixture of the two proteins, then separating them by immunoprecipitation, the difference in susceptibility was shown to be due to the greater reactivity of transferrin iron-binding groups, rather than protective groups on the lactoferrin molecule. The iron-saturated proteins were much more resistant to oxidative modification than the apoproteins. The greater resistance of apolactoferrin should be advantageous for maintaining its iron binding capacity when co-released with myeloperoxidase and reactive oxygen species from stimulated neutrophils.

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