scholarly journals Natively Oxidized Amino Acid Residues in the Spinach Cytochrome b6f Complex

2017 ◽  
Author(s):  
Ryan M. Taylor ◽  
Larry Sallans ◽  
Laurie K. Frankel ◽  
Terry M. Bricker
Keyword(s):  
Amino Acid ◽  
Oxidative Modification ◽  
Oxygenic Photosynthesis ◽  
Ros Generation ◽  
Ros Production ◽  
Amino Acid Residues ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur ◽  
The Subject ◽  
Oxidatively Modified

AbstractThe cytochrome b6f complex of oxygenic photosynthesis produces substantial levels of reactive oxygen species (ROS). It has been observed that the ROS production rate by b6f is 10-20 fold higher than that observed for the analogous respiratory cytochrome bc1 complex. The types of ROS produced (O2•−,1O2, and, possibly, H2O2) and the site(s) of ROS production within the b6f complex has been the subject of some debate. Proposed sources of ROS have include the heme bp, PQp•− (possible sources for O2•−), the Rieske iron-sulfur cluster (possible source of O2•− and/or H2O2), Chl a (possible source of 1O2) and heme Cn (possible source of O2•− and/or H2O2). Our working hypothesis is that amino acid residues proximal to the ROS production sites will be more susceptible to oxidative modification than distant residues. In the current study, we have identified natively oxidized amino acid residues in the subunits of the spinach cytochrome b6f complex. The oxidized residues were identified by tandem mass spectrometry using the MassMatrix Program. Our results indicate that numerous residues, principally localized near p-side cofactors and Chl a, were oxidatively modified. We hypothesize that these sites are sources for ROS generation in the spinach cytochrome b6f complex.

scholarly journals Natively Oxidized Amino Acid Residues in the Spinach PS I-LHC I Supercomplex

2019 ◽  
Author(s):  
Ravindra Kale ◽  
Larry Sallans ◽  
Laurie K. Frankel ◽  
Terry M. Bricker
Keyword(s):  
Amino Acid ◽  
Oxidative Modification ◽  
Ros Generation ◽  
Ros Production ◽  
Amino Acid Residues ◽  
Ps Ii ◽  
Chl A ◽  
Ps I ◽  
Close Proximity ◽  
Oxidatively Modified

AbstractReactive oxygen species (ROS) production is an unavoidable byproduct of electron transport under aerobic conditions. Photosystem II (PS II), the cytochrome b6f complex and Photosystem I (PS I) are all demonstrated sources of ROS. It has been proposed that PS I produces substantial levels of a variety of ROS including 1O2, H2O2 and, possibly, , however, the site(s) of ROS production within PS I has been the subject of significant debate. We hypothesize that amino acid residues close to the sites of ROS generation will be more susceptible to oxidative modification than distant residues. In this study, we have identified oxidized amino acid residues in spinach PS I which was isolated from field-grown spinach. The modified residues were identified by high-resolution tandem mass spectrometry. As expected, many of the modified residues lie on the surface of the complex. However, a well-defined group of oxidized residues, both buried and surface-exposed, lead from the chl a’ of P700 to the surface of PS I. These residues (PsaB: 609F, 611E, 617M, 619W, 620L, and PsaF: 139L, 142A,143D) may identify a preferred route for ROS, probably 1O2, to egress the complex from the vicinity of P700. Additionally, two buried residues located in close proximity to A1B (PsaB:712H and 714S) were modified, which may be consistent with A1B being a source of . Surprisingly, no oxidatively modified residues were identified in close proximity to the 4Fe-FS clusters FX, FA or FB. These cofactors had been identified as a principal targets for ROS damage in the photosystem. Finally, a large number of residues located in the hydrophobic cores of Lhca1-Lhca4 are oxidatively modified. These appear to be the result of 1O2 production by the distal antennae for the photosystem.

scholarly journals Mitochondrial ROS promote macrophage pyroptosis by inducing GSDMD oxidation

2019 ◽  
Vol 11 (12) ◽  
pp. 1069-1082 ◽  
Author(s):  
Yufang Wang ◽  
Peiliang Shi ◽  
Qin Chen ◽  
Zan Huang ◽  
Dayuan Zou ◽  
...  
Keyword(s):  
Amino Acid ◽  
Nlrp3 Inflammasome ◽  
De Novo ◽  
Oxidative Modification ◽  
Ros Generation ◽  
Inflammasome Activation ◽  
Amino Acid Residues ◽  
Caspase 1 ◽  
Hydrogen Peroxide Treatment ◽  
Mitochondrial Ros

Abstract Disrupted mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) generation are often associated with macrophage pyroptosis. It remains unclear how these forms of mitochondrial dysfunction relate to inflammasome activation and gasdermin-D (Gsdmd) cleavage, two central steps of the pyroptotic process. Here, we also found MMP collapse and ROS generation induced by Nlrp3 inflammasome activation as previous studies reported. The elimination of ROS alleviated the cleavage of Gsdmd, suggesting that Gsdmd cleavage occurs downstream of ROS release. Consistent with this result, hydrogen peroxide treatment augmented the cleavage of Gsdmd by caspase-1. Indeed, four amino acid residues of Gsdmd were oxidized under oxidative stress in macrophages. The efficiency of Gsdmd cleavage by inflammatory caspase-1 was dramatically reduced when oxidative modification was blocked by mutation of these amino acid residues. These results demonstrate that Gsdmd oxidation serves as a de novo mechanism by which mitochondrial ROS promote Nlrp3 inflammasome-dependent pyroptotic cell death.

Peroxynitrite and Nitric Oxide Differently Target the Iron−Sulfur Cluster and Amino Acid Residues of Human Iron Regulatory Protein 1†

Biochemistry ◽  
2003 ◽  
Vol 42 (25) ◽  
pp. 7648-7654 ◽  
Author(s):  
Emmanuelle Soum ◽  
Xavier Brazzolotto ◽  
Charilaos Goussias ◽  
Cécile Bouton ◽  
Jean-Marc Moulis ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Amino Acid ◽  
Regulatory Protein ◽  
Iron Regulatory Protein ◽  
Amino Acid Residues ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Iron Regulatory Protein 1

scholarly journals Oxidative Modification of LHC II Associated with Photosystem II and PS I-LHC I-LHC II Membranes

2021 ◽  
Author(s):  
Ravindra S Kale ◽  
Jacob Seep ◽  
Larry Sallans ◽  
Laurie K Frankel ◽  
Terry M. Bricker
Keyword(s):  
Amino Acid ◽  
Photosystem Ii ◽  
Oxidative Modification ◽  
Ros Generation ◽  
Hydrophobic Core ◽  
Amino Acid Residues ◽  
Lhc Ii ◽  
Ps Ii ◽  
Ps I ◽  
Lhc I

Under aerobic conditions the production of Reactive Oxygen Species (ROS) by electron transport chains is unavoidable, and occurs in both autotrophic and heterotrophic organisms. In photosynthetic organisms both Photosystem II (PS II) and Photosystem I (PS I), in addition to the cytochrome b6/f complex, are demonstrated sources of ROS. All of these membrane protein complexes exhibit oxidative damage when isolated from field-grown plant material. An additional possible source of ROS in PS I and PS II is the distal, chlorophyll-containing light-harvesting array LHC II, which is present in both photosystems. These serve as possible sources of 1O2 produced by the interaction of 3O2 with 3chl* produced by intersystem crossing. We have hypothesized that amino acid residues close to the sites of ROS generation will be more susceptible to oxidative modification than distant residues. In this study, we have identified oxidized amino acid residues in a subset of the spinach LHC II proteins (Lhcb1 and Lhcb2) that were associated with either PS II membranes (i.e. BBYs) or PS I-LHC I-LHC II membranes, both of which were isolated from field-grown spinach. We identified oxidatively modified residues by high-resolution tandem mass spectrometry. Interestingly, two different patterns of oxidative modification were evident for the Lhcb1 and Lhcb2 proteins from these different sources. In the LHC II associated with PS II membranes, oxidized residues were identified to be located on the stromal surface of Lhcb1 and, to a much lesser extent, Lhcb2. Relatively few oxidized residues were identified as buried in the hydrophobic core of these proteins. The LHC II associated with PS I-LHC I-LHC II membranes, however, exhibited fewer surface-oxidized residues but, rather a large number of oxidative modifications buried in the hydrophobic core regions of both Lhcb1 and Lhcb2, adjacent to the chlorophyll prosthetic groups. These results appear to indicate that ROS, specifically 1O2, can modify the Lhcb proteins associated with both photosystems and that the LHC II associated with PS II membranes represent a different population from the LHC II associated with PS I-LHC I-LHC II membranes.

scholarly journals The mitochondrial monothiol glutaredoxin S15 is essential for iron-sulfur protein maturation in Arabidopsis thaliana

2015 ◽  
Vol 112 (44) ◽  
pp. 13735-13740 ◽  
Author(s):  
Anna Moseler ◽  
Isabel Aller ◽  
Stephan Wagner ◽  
Thomas Nietzel ◽  
Jonathan Przybyla-Toscano ◽  
...  
Keyword(s):  
Amino Acid Residues ◽  
Iron Sulfur Cluster ◽  
Growth Defects ◽  
Iron Sulfur ◽  
Iron Sulfur Proteins ◽  
Dna Insertion ◽  
Sulfur Protein ◽  
Metabolic Reactions ◽  
Insertion Mutants

The iron-sulfur cluster (ISC) is an ancient and essential cofactor of many proteins involved in electron transfer and metabolic reactions. In Arabidopsis, three pathways exist for the maturation of iron-sulfur proteins in the cytosol, plastids, and mitochondria. We functionally characterized the role of mitochondrial glutaredoxin S15 (GRXS15) in biogenesis of ISC containing aconitase through a combination of genetic, physiological, and biochemical approaches. Two Arabidopsis T-DNA insertion mutants were identified as null mutants with early embryonic lethal phenotypes that could be rescued by GRXS15. Furthermore, we showed that recombinant GRXS15 is able to coordinate and transfer an ISC and that this coordination depends on reduced glutathione (GSH). We found the Arabidopsis GRXS15 able to complement growth defects based on disturbed ISC protein assembly of a yeast Δgrx5 mutant. Modeling of GRXS15 onto the crystal structures of related nonplant proteins highlighted amino acid residues that after mutation diminished GSH and subsequently ISC coordination, as well as the ability to rescue the yeast mutant. When used for plant complementation, one of these mutant variants, GRXS15K83/A, led to severe developmental delay and a pronounced decrease in aconitase activity by approximately 65%. These results indicate that mitochondrial GRXS15 is an essential protein in Arabidopsis, required for full activity of iron-sulfur proteins.

scholarly journals The influence of metals of variable valence on the oxidative modification of albumin amino acid residues

2021 ◽  
Vol 9 (3) ◽  
pp. 369-376
Author(s):  
O.A. Zav’yalova ◽  
◽  
Yu.A. Marsyanova ◽  
Yu.V. Abalenikhinа ◽  
A.F. Ishtulin ◽  
...  
Keyword(s):  
Amino Acid ◽  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Bovine Serum ◽  
Mixed Valence ◽  
Oxidative Modification ◽  
Amino Acid Residues ◽  
Variable Valence ◽  
Carbonyl Derivatives ◽  
Derivatives Of

BACKGROUND: The constancy of the protein composition of the body is one of the most important conditions for normal vital activity. Deviations in the content of the main bioelements, in particular, mixed valence metals, caused by environmental factors, improper nutrition and other factors, lead to various disorders. One of the properties of metals of mixed valence is the abil-ity to cause metal-catalyzed oxidation of proteins in joint action with active forms of oxygen. It seems interesting to study the oxidative modification of the amino acid residues of albumin and the change in its properties. AIM: To study the effect of reactive oxygen intermediates generated by the Fenton reaction in the presence of Fe2+ and Cu2+ on the oxidative modification of amino acid residues of bovine serum albumin. MATERIALS AND METHODS: The study was carried out on bovine serum albumin (BSA), which was incubated for 2 hours in a mixture of Fenton's reagents – FeSO4 + H2O2 and in a mixture of СuSO4 + H2O2. The quantitative protein content in the samples was determined with the bromcresol green reagent (Albumin-Olvex). The content of carbonyl derivatives of proteins was estimated by the method of R.L. Levine modified by E.E. Dubinina. The content of thiol groups in albumin samples from the control and experimental groups was determined by the Ellman method with DTNB (under non-denaturing conditions. RESULTS: The presented results demonstrate that under the action of Cu2+ ions, the formation of carbonyl derivatives of aliphatic amino acids of albumin is less than in the presence of Fe2+, which can be explained by the different degrees of albumin affinity to metals of variable valence. The rate of mobility of oxidatively modified albumin in polyacrylamide gel decreases, which is explained by protein aggregation due to bityrosine cross-links. CONCLUSION: Variable valence metals affect the modification of albumin. The change in the functional properties of the protein is of physiological significance, including the case of extracellular mobilization of iron and copper.

scholarly journals Copper Efflux Is Induced during Anaerobic Amino Acid Limitation in Escherichia coli To Protect Iron-Sulfur Cluster Enzymes and Biogenesis

2013 ◽  
Vol 195 (20) ◽  
pp. 4556-4568 ◽  
Author(s):  
D. K. C. Fung ◽  
W. Y. Lau ◽  
W. T. Chan ◽  
A. Yan
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Iron Sulfur Cluster ◽  
Sulfur Cluster ◽  
Iron Sulfur

scholarly journals Conformational stability of bovine α-crystallin. Evidence for a destabilizing effect of ascorbate

1992 ◽  
Vol 287 (1) ◽  
pp. 107-112 ◽  
Author(s):  
S A Santini ◽  
A Mordente ◽  
E Meucci ◽  
G A D Miggiano ◽  
G E Martorana
Keyword(s):  
Amino Acid ◽  
Conformational Stability ◽  
Gel Filtration ◽  
Protein Molecule ◽  
Oxidative Modification ◽  
Amino Acid Residues ◽  
Alpha Crystallin ◽  
Protein Dissociation ◽  
Covalent Adducts ◽  
Polypeptide Chains

Short-term incubation of bovine alpha-crystallin with ascorbate alters the protein conformational stability. The denaturation curves with urea and guanidinium-chloride show different patterns, suggesting a deviation from a two-state mechanism owing to the presence of one or more intermediates in the unfolding of ascorbate-modified alpha-crystallin. Furthermore, the latter protein profiles are shifted to lower denaturant concentrations indicating a destabilizing action of ascorbate, which is capable of facilitating protein dissociation into subunits as demonstrated by gel filtration with 1.5 M-urea. The decrease in conformational stability cannot be ascribed to any major structural alteration, but rather to localized changes in the protein molecule. In fact, no difference between native and ascorbate-treated alpha-crystallin can be detected by amino acid analysis but perturbation of the tryptophan and tyrosine environment is indicated by alterations in intrinsic fluorescence. Furthermore, turbidity and light-scattering measurements suggest an involvement of the lysine side chains, since aggregability patterns with acetylsalicylic acid are significantly altered. The ascorbate-destabilizing effect on the conformational stability of alpha-crystallin, probably exerted through oxidative modification of amino acid residues and/or the formation of covalent adducts, provokes unfavourable steric interactions between residues along the polypeptide chains, thus favouring aggregation and insolubilization of crystallins which can lead to cataract formation, as also demonstrated by proteolytic digestion patterns which show a lower rate of degradation of the ascorbate-modified alpha-crystallin.

scholarly journals An Activated Glutamate Residue Identified in Photosystem II at the Interface between the Manganese-stabilizing Subunit and the D2 Polypeptide

2007 ◽  
Vol 282 (38) ◽  
pp. 27802-27809 ◽  
Author(s):  
Sascha Rexroth ◽  
Catherine C. L. Wong ◽  
Jessica H. Park ◽  
John R. Yates ◽  
Bridgette A. Barry
Keyword(s):  
Amino Acid ◽  
Photosystem Ii ◽  
Oxygenic Photosynthesis ◽  
Photosynthetic Oxygen Evolution ◽  
Amino Acid Residues ◽  
Post Translational Modification ◽  
Steady State Rate ◽  
Reactive Groups ◽  
Psii Subunits

Photosystem II (PSII) catalyzes the oxidation of water during oxygenic photosynthesis. PSII is composed both of intrinsic subunits, such as D1, D2, and CP47, and extrinsic subunits, such as the manganese-stabilizing subunit (MSP). Previous work has shown that amines covalently bind to amino acid residues in the CP47, D1, and D2 subunits of plant and cyanobacterial PSII, and that these covalent reactions are prevented by the addition of chloride in plant preparations depleted of the 18- and 24-kDa extrinsic subunits. It has been proposed that these reactive groups are carbonyl-containing, post-translationally modified amino acid side chains (Ouellette, A. J. A., Anderson, L. B., and Barry, B. A. (1998) Proc. Natl. Acad. Sci. U. S. A. 95, 2204–2209 and Anderson, L. B., Ouellette, A. J. A., and Barry, B. A. (2000) J. Biol. Chem. 275, 4920–4927). To identify the amino acid binding site in the spinach D2 subunit, we have employed a biotin-amine labeling reagent, which can be used in conjunction with avidin affinity chromatography to purify biotinylated peptides from the PSII complex. Multidimensional chromato-graphic separation and multistage mass spectrometry localizes a novel post-translational modification in the D2 subunit to glutamate 303. We propose that this glutamate is activated for amine reaction by post-translational modification. Because the modified glutamate is located at a contact site between the D2 and manganese-stabilizing subunits, we suggest that the modification is important in vivo in stabilizing the interaction between these two PSII subunits. Consistent with this conclusion, mutations at the modified glutamate alter the steady-state rate of photosynthetic oxygen evolution.

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