共查询到20条相似文献，搜索用时 62 毫秒
1.
Yue Liu James Clement Ross Grant Perminder Sachdev Nady Braidy 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2527-2532
Background
Nicotinamide adenine dinucleotide (NAD+) is an essential pyridine nucleotide that is currently investigated as an important target to extend lifespan and health span. Age-related NAD+ depletion due to the accumulation of oxidative stress is associated with reduced energy production, impaired DNA repair and genomic instability.Scope of review
NAD+ levels can be elevated therapeutically using NAD+ precursors or through lifestyle modifications including exercise and caloric restriction. However, high amounts of NAD+ may be detrimental in cancer progression and may have deleterious immunogenic roles.Major conclusions
Standardized quantitation of NAD+ and related metabolites may therefore represent an important component of NAD+ therapy.General significance
Quantitation of NAD+ may serve dual roles not only as an ageing biomarker, but also as a diagnostic tool for the prevention of malignant disorders. 相似文献2.
Salome Kylarova Katarina Psenakova Petr Herman Veronika Obsilova Tomas Obsil 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(10):2304-2313
Background
Calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2), a member of the Ca?2+/calmodulin-dependent kinase (CaMK) family, functions as an upstream activator of CaMKI, CaMKIV and AMP-activated protein kinase. Thus, CaMKK2 is involved in the regulation of several key physiological and pathophysiological processes. Previous studies have suggested that Ca2+/CaM binding may cause unique conformational changes in the CaMKKs compared with other CaMKs. However, the underlying mechanistic details remain unclear.Methods
In this study, hydrogen-deuterium exchange coupled to mass spectrometry, time-resolved fluorescence spectroscopy, small-angle x-ray scattering and chemical cross-linking were used to characterize Ca2+/CaM binding-induced structural changes in CaMKK2.Results
Our data suggest that: (i) the CaMKK2 kinase domain interacts with the autoinhibitory region (AID) through the N-terminal lobe of the kinase domain including the RP insert, a segment important for targeting downstream substrate kinases; (ii) Ca2+/CaM binding affects the structure of several regions surrounding the ATP-binding pocket, including the activation segment; (iii) although the CaMKK2:Ca2+/CaM complex shows high conformational flexibility, most of its molecules are rather compact; and (iv) AID-bound Ca2+/CaM transiently interacts with the CaMKK2 kinase domain.Conclusions
Interactions between the CaMKK2 kinase domain and the AID differ from those of other CaMKs. In the absence of Ca2+/CaM binding the autoinhibitory region inhibits CaMKK2 by both blocking access to the RP insert and by affecting the structure of the ATP-binding pocket.General significance
Our results corroborate the hypothesis that Ca2+/CaM binding causes unique conformational changes in the CaMKKs relative to other CaMKs. 相似文献3.
4.
Ludmila A. Kasatkina Vitaliy P. Gumenyuk Eva M. Sturm Akos Heinemann Tytus Bernas Irene O. Trikash 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2701-2713
Background
Neurosecretion is the multistep process occurring in separate spatial and temporal cellular boundaries which complicates its comprehensive analysis. Most of the research are focused on one distinct stage of synaptic vesicle recycling. Here, we describe approaches for complex analysis of synaptic vesicle (SV) endocytosis and separate steps of exocytosis at the level of presynaptic bouton and highly purified SVs.Methods
Proposed fluorescence-based strategies and analysis of neurotransmitter transport provided the advantages in studies of exocytosis steps. We evaluated SV docking/tethering, their Ca2+-dependent fusion and release of neurotransmitters gamma-aminobutyric acid (GABA) and glutamate in two animal models.Results
Approaches enabled us to study: 1) endocytosis/Ca2+-dependent release of fluorescent carbon nanodots (CNDs) during stimulation of nerve terminals; 2) the action of levetiracetam, modulator of SV glycoprotein SV2, on fusion competence of SVs and stimulated release of GABA and glutamate; 3) impairments of several steps of neurosecretion under vitamin D3 deficiency.Conclusions
Our algorithm enabled us to verify the method validity for multidimensional analysis of SV turnover. By increasing SV docking and the size of readily releasable pool (RRP), levetiracetam is able to selectively enhance the stimulated GABA secretion in hippocampal neurons. Findings suggest that SV2 regulates RRP through impact on the number of docked/primed SVs.General significance
Methodology can be widely applied to study the stimulated neurosecretion in presynapse, regulation of SV docking, their Ca2+-dependent fusion with target membranes, quantitative analysis of expression of neuron-specific proteins, as well as for testing the efficiency of pre-selected designed neuroactive substances. 相似文献5.
Wataru Yoshida Mizuki Terasaka Saowalak Laddachote Isao Karube 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(9):1933-1937
Background
DNA methylation at the 5-position of cytosine is an epigenetic modification of CpG dinucleotides. In addition to CpG methylation, the G-quadruplex (G4) structure has been reported as a regulator of gene expression. The identification of G4 forming sequences in CpG islands suggests an involvement of CpG-methylated G4 structures in biological processes; however, few reports have addressed the effects of CpG methylation on G4 structure.Methods
The thermostability of a methylated, 21-mer G4 structure located on the vascular endothelial growth factor (VEGF) gene promoter containing four CpG sites (C1, C6, C11, and C17) were investigated using circular dichroism (CD) spectral analysis.Results
CD melting analysis revealed that VEGF G4 was stabilized by a single CpG methylation on C11 in the presence of Na+ and Mg2+. However, either C1 or C11 methylation enhanced VEGF G4 thermal stability in the presence of K+.Conclusions
Single CpG methylation appears to enhance VEGF G4 thermostability in a manner dependent on both the CpG methylation site and cation type.General significance
These results are expected to contribute to the elucidation of the roles of CpG methylation-stabilized G4 structures in biological processes. 相似文献6.
Jia Hao Yeo Chanukya K. Colonne Nuren Tasneem Matthew P. Cosgriff Stuart T. Fraser 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(2):466-471
Background
A healthy human can produce over 1?×?1015 blood cells throughout their life. This remarkable amount of biomass requires a concomitantly vast amount of iron to generate functional haemoglobin and functional erythrocytes.Scope of the review
Erythroblasts form multicellular clusters with macrophages in the foetal liver, bone marrow and spleen termed erythroblastic islands. How the central erythroblastic island macrophage co-ordinates the supply of iron to the developing erythroblasts will be a central focus of this review.Major conclusion
Despite being studied for over 60?years, the mechanisms by which the erythroblastic island niche serves to control erythroid cell iron metabolism are poorly resolved.General significance
Over 2 billion people suffer from some form of anaemia. Iron deficiency anaemia is the most prevalent form of anaemia. Therefore, understanding the processes by which iron is trafficked to, and metabolised in developing erythrocytes, is crucially important. 相似文献7.
Alex Ferrandi Federica Castani Mauro Pitaro Sara Tagliaferri Claire Bouthier de la Tour Rosa Alduina Suzanne Sommer Mauro Fasano Paola Barbieri Monica Mancini Ian Marc Bonapace 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(1):118-129
Background
Deinococcus radiodurans R1 (DR) survives conditions of extreme desiccation, irradiation and exposure to genotoxic chemicals, due to efficient DNA breaks repair, also through Mn2+ protection of DNA repair enzymes.Methods
Possible annotated domains of the DR1533 locus protein (Shp) were searched by bioinformatic analysis. The gene was cloned and expressed as fusion protein. Band-shift assays of Shp or the SRA and HNH domains were performed on oligonucleotides, genomic DNA from E. coli and DR. shp knock-out mutant was generated by homologous recombination with a kanamycin resistance cassette.Results
DR1533 contains an N-terminal SRA domain and a C-terminal HNH motif (SRA-HNH Protein, Shp). Through its SRA domain, Shp binds double-strand oligonucleotides containing 5mC and 5hmC, but also unmethylated and mismatched cytosines in presence of Mn2+. Shp also binds to Escherichia coli dcm+ genomic DNA, and to cytosine unmethylated DR and E. coli dcm? genomic DNAs, but only in presence of Mn2+. Under these binding conditions, Shp displays DNAse activity through its HNH domain. Shp KO enhanced >100 fold the number of spontaneous mutants, whilst the treatment with DNA double strand break inducing agents enhanced up to 3-log the number of survivors.Conclusions
The SRA-HNH containing protein Shp binds to and cuts 5mC DNA, and unmethylated DNA in a Mn2+ dependent manner, and might be involved in faithful genome inheritance maintenance following DNA damage.General significance
Our results provide evidence for a potential role of DR Shp protein for genome integrity maintenance, following DNA double strand breaks induced by genotoxic agents. 相似文献8.
Nathalie Lejal Sandrine Truchet Edna Bechor Edwige Bouguyon Vijay Khedkar Nicolas Bertho Jasmina Vidic Pierre Adenot Stéphanie Solier Edgar Pick Anny Slama-Schwok 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(6):1263-1275
Background
Targeting cells of the host immune system is a promising approach to fight against Influenza A virus (IAV) infection. Macrophage cells use the NADPH oxidase-2 (NOX2) enzymatic complex as a first line of defense against pathogens by generating superoxide ions O2– and releasing H2O2. Herein, we investigated whether targeting membrane -embedded NOX2 decreased IAV entry via raft domains and reduced inflammation in infected macrophages.Methods
Confocal microscopy and western blots monitored levels of the viral nucleoprotein NP and p67phox, NOX2 activator subunit, Elisa assays quantified TNF-α levels in LPS or IAV-activated mouse or porcine alveolar macrophages pretreated with a fluorescent NOX inhibitor, called nanoshutter NS1.Results
IAV infection in macrophages promoted p67phox translocation to the membrane, rafts clustering and activation of the NOX2 complex at early times. Disrupting rafts reduced intracellular viral NP. NS1 markedly reduced raft clustering and viral entry by binding to the C-terminal of NOX2 also characterized in vitro. NS1 decrease of TNF-α release depended on the cell type.Conclusion
NOX2 participated in IAV entry and raft-mediated endocytosis. NOX2 inhibition by NS1 reduced viral entry. NS1 competition with p67phox for NOX2 binding shown by in silico models and cell-free assays was in agreement with NS1 inhibiting p67phox translocation to membrane-embedded NOX2 in mouse and porcine macrophages.General significance
We introduce NS1 as a compound targeting NOX2, a critical enzyme controlling viral levels and inflammation in macrophages and discuss the therapeutic relevance of targeting the C-terminal of NADPH oxidases by probes like NS1 in viral infections. 相似文献9.
Attilio Vittorio Vargiu Venkata Krishnan Ramaswamy Ivana Malvacio Giuliano Malloci Ulrich Kleinekathöfer Paolo Ruggerone 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(4):836-845
Background
Efflux pumps of the Resistance-Nodulation-cell Division superfamily confer multi-drug resistance to Gram-negative bacteria. The most-studied polyspecific transporter belonging to this class is the inner-membrane trimeric antiporter AcrB of Escherichia coli. In previous studies, a functional rotation mechanism was proposed for its functioning, according to which the three monomers undergo concerted conformational changes facilitating the extrusion of substrates. However, the molecular determinants and the energetics of this mechanism still remain unknown, so its feasibility must be proven mechanistically.Methods
A computational protocol able to mimic the functional rotation mechanism in AcrB was developed. By using multi-bias molecular dynamics simulations we characterized the translocation of the substrate doxorubicin driven by conformational changes of the protein. In addition, we estimated for the first time the free energy profile associated to this process.Results
We provided a molecular view of the process in agreement with experimental data. Moreover, we showed that the conformational changes occurring in AcrB enable the formation of a layer of structured waters on the internal surface of the transport channel. This water layer, in turn, allows for a fairly constant hydration of the substrate, facilitating its diffusion over a smooth free energy profile.Conclusions
Our findings reveal a new molecular mechanism of polyspecific transport whereby water contributes by screening potentially strong substrate-protein interactions.General significance
We provided a mechanistic understanding of a fundamental process related to multi-drug transport. Our results can help rationalizing the behavior of other polyspecific transporters and designing compounds avoiding extrusion or inhibitors of efflux pumps. 相似文献10.
Sumangala Shetty Paul R. Copeland 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(11):2506-2510
Background
Selenoprotein synthesis requires the reinterpretation of a UGA stop codon as one that encodes selenocysteine (Sec), a process that requires a set of dedicated translation factors. Among the mammalian selenoproteins, Selenoprotein P (SELENOP) is unique as it contains a selenocysteine-rich domain that requires multiple Sec incorporation events.Scope of review
In this review we elaborate on new data and current models that provide insight into how SELENOP is made.Major conclusions
SELENOP synthesis requires a specific set of factors and conditions.General significance
As the key protein required for proper selenium distribution, SELENOP stands out as a lynchpin selenoprotein that is essential for male fertility, proper neurologic function and selenium metabolism. 相似文献11.
Zahia Touat-Hamici Anne-Laure Bulteau Juliusz Bianga Hélène Jean-Jacques Joanna Szpunar Ryszard Lobinski Laurent Chavatte 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(11):2493-2505
Background
Selenoproteins (25 genes in human) co-translationally incorporate selenocysteine using a UGA codon, normally used as a stop signal. The human selenoproteome is primarily regulated by selenium bioavailability with a tissue-specific hierarchy.Methods
We investigated the hierarchy of selenoprotein expression in response to selenium concentration variation in four cell lines originating from kidney (HEK293, immortalized), prostate (LNCaP, cancer), skin (HaCaT, immortalized) and liver (HepG2, cancer), using complementary analytical methods. We performed (i) enzymatic activity, (ii) RT-qPCR, (iii) immuno-detection, (iv) selenium-specific mass spectrometric detection after non-radioactive 76Se labeling of selenoproteins, and (v) luciferase-based reporter constructs in various cell extracts.Results
We characterized cell-line specific alterations of the selenoproteome in response to selenium variation that, in most of the cases, resulted from a translational control of gene expression. We established that UGA-selenocysteine recoding efficiency, which depends on the nature of the SECIS element, dictates the response to selenium variation.Conclusions
We characterized that selenoprotein hierarchy is cell-line specific with conserved features. This analysis should be done prior to any experiments in a novel cell line.General significance
We reported a strategy based on complementary methods to evaluate selenoproteome regulation in human cells in culture. 相似文献12.
Dunja Urbančič Anita Kotar Alenka Šmid Marko Jukič Stanislav Gobec Lars-Göran Mårtensson Janez Plavec Irena Mlinarič-Raščan 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(1):182-190
Background
Methylation driven by thiopurine S-methylatransferase (TPMT) is crucial for deactivation of cytostatic and immunosuppressant thiopurines. Despite its remarkable integration into clinical practice, the endogenous function of TPMT is unknown.Methods
To address the role of TPMT in methylation of selenium compounds, we established the research on saturation transfer difference (STD) and 77Se NMR spectroscopy, fluorescence measurements, as well as computational molecular docking simulations.Results
Using STD NMR spectroscopy and fluorescence measurements of tryptophan residues in TPMT, we determined the binding of selenocysteine (Sec) to human recombinant TPMT. By comparing binding characteristics of Sec in the absence and in the presence of methyl donor, we confirmed S-adenosylmethionine (SAM)-induced conformational changes in TPMT. Molecular docking analysis positioned Sec into the active site of TPMT with orientation relevant for methylation reaction. Se-methylselenocysteine (MeSec), produced in the enzymatic reaction, was detected by 77Se NMR spectroscopy. A direct interaction between Sec and SAM in the active site of rTPMT and the formation of both products, MeSec and S-adenosylhomocysteine, was demonstrated using NMR spectroscopy.Conclusions
The present study provides evidence on in vitro methylation of Sec by rTPMT in a SAM-dependant manner.General significance
Our results suggest novel role of TPMT and demonstrate new insights into enzymatic modifications of the 21st amino acid. 相似文献13.
Seong-Cheol Park Il Ryong Kim Jin-Young Kim Yongjae Lee Eun-Ji Kim Ji Hyun Jung Young Jun Jung Mi-Kyeong Jang Jung Ro Lee 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2545-2554
Background
It remains an open question whether plant phloem sap proteins are functionally involved in plant defense mechanisms.Methods
The antifungal effects of two profilin proteins from Arabidopsis thaliana, AtPFN1 and AtPFN2, were tested against 11 molds and 4 yeast fungal strains. Fluorescence profiling, biophysical, and biochemical analyses were employed to investigate their antifungal mechanism.Results
Recombinant AtPFN1 and AtPFN2 proteins, expressed in Escherichia coli, inhibited the cell growth of various pathogenic fungal strains at concentrations ranging from 10 to 160?μg/mL. The proteins showed significant intracellular accumulation and cell-binding affinity for fungal cells. Interestingly, the AtPFN proteins could penetrate the fungal cell wall and membrane and act as inhibitors of fungal growth via generation of cellular reactive oxygen species and mitochondrial superoxide. This triggered the AtPFN variant-induced cell apoptosis, resulting in morphological changes in the cells.Conclusion
PFNs may play a critical role as antifungal proteins in the Arabidopsis defense system against fungal pathogen attacks.General significance
The present study indicates that two profilin proteins, AtPFN1 and AtPFN2, can act as natural antimicrobial agents in the plant defense system. 相似文献14.
15.
Cristina Pérez-Arnaiz Natalia Busto Javier Santolaya José M. Leal Giampaolo Barone Begoña García 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(3):522-531
Background
Stabilization of G-quadruplex helices by small ligands has attracted growing attention because they inhibit the activity of the enzyme telomerase, which is overexpressed in > 80% cancer cells. TMPyP4, one of the most studied G-quadruplex ligands, is used as a model to show that the ligands can exhibit different binding features with different conformations of a human telomeric specific sequence.Methods
UV–Vis, FRET melting Assay, Isothermal Titration Calorimetry, Time-resolved Fluorescence lifetime, T-Jump and Molecular Dynamics.Results
TMPyP4 yields two different complexes with two Tel22 telomeric conformations in the presence of Na+ or K+. T-Jump kinetic experiments show that the rates of formation and dissociation of these complexes in the ms time scale differ by one order of magnitude. MD simulations reveal that, in K+ buffer, “hybrid 1” conformation yields kinetic constants on interaction with TMPyP4 one order lower than “hybrid 2”. The binding involves π–π stacking with external loop bases.Conclusions
For the first time we show that for a particular buffer TMPyP4 interacts in a kinetically different way with the two Tel22 conformations even if the complexes formed are thermodynamically indistinguishable.General significance
G-quadruplexes, endowed with technological applications and potential impact on regulation mechanisms, define a new research field. The possibility of building different conformations from same sequence is a complex issue that confers G-quadruplexes very interesting features. The obtaining of reliable kinetic data constitutes an efficient tool to determine reaction mechanisms between conformations and small molecules. 相似文献16.
Shruti Chakraborty Sayak Ganguli Aritra Chowdhury Michael Ibba Rajat Banerjee 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(8):1801-1809
Background
Under oxidative stress cytoplasmic aminoacyl-tRNA synthetase (aaRSs) substrate specificity can be compromised, leading to tRNA mischarging and mistranslation of the proteome. Whether similar processes occur in mitochondria, which are major cellular sources of reactive oxygen species (ROS), is unknown. However, relaxed substrate specificity in yeast mitochondrial phenylalanyl-tRNA synthetase (ScmitPheRS) has been reported to increase tRNA mischarging and blocks mitochondrial biogenesis.Methods
Non-reducing denaturing PAGE, cysteine reactivity studies, MALDI-TOF mass spectrometry, enzyme assay, western blot, growth assay, circular dichroism, dynamic light scattering and fluorescence spectroscopy were used to study the effect of oxidative stress on ScmitPheRS activity.Results
ScmitPheRS is reversibly inactivated under oxidative stress. The targets for oxidative inactivation are two conserved cysteine residues resulting in reversible intra-molecular disulfide bridge formation. Replacement of either conserved cysteine residue increased viability during growth under oxidative stress.Conclusion
Formation of intra-molecular disulfide bridge under oxidative stress hinders the tRNAPhe binding of the enzyme, thus inactivating ScmitPheRS reversibly.General significance
The ScmitPheRS activity is compromised under oxidative stress due to formation of intra-molecular disulfide bridge. The sensitivity of ScmitPheRS to oxidation may provide a protective mechanism against error-prone translation under oxidative stress. 相似文献17.
Gildeíde Aparecida Costa Sávio Bastos de Souza Layz Ribeiro da Silva Teixeira Lev A. Okorokov Andrea Cristina Vetö Arnholdt Anna L. Okorokova-Façanha Arnoldo Rocha Façanha 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(3):684-691
Background
V-ATPase interactions with cholesterol enriched membrane microdomains have been related to metastasis in a variety of cancers, but the underlying mechanism remains at its beginnings. It has recently been reported that the inhibition of this H+ pump affects cholesterol mobilization to the plasma membrane.Methods
Inhibition of melanoma cell migration and invasiveness was assessed by wound healing and Transwell assays in murine cell lines (B16F10 and Melan-A). V-ATPase activity was measured in vitro by ATP hydrolysis and H+ transport in membrane vesicles, and intact cell H+ fluxes were measured by using a non-invasive Scanning Ion-selective Electrode Technique (SIET).Results
Cholesterol depletion by 5 mM MβCD was found to be inhibitory to the hydrolytic and H+ pumping activities of the V-ATPase of melanoma cell lines, as well as to the migration and invasiveness capacities of these cells. Nearly the same effects were obtained using concanamycin A, a specific inhibitor of V-ATPase, which also promoted a decrease of the H+ efflux in live cells at the same extent of MβCD.Conclusions
We found that cholesterol depletion significantly affects the V-ATPase activity and the initial metastatic processes following a profile similar to those observed in the presence of the V-ATPase specific inhibitor, concanamycin.General significance
The results shed new light on the functional role of the interactions between V-ATPases and cholesterol-enriched microdomains of cell membranes that contribute with malignant phenotypes in melanoma. 相似文献18.
Marilene Demasi Fernanda Marques da Cunha 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2948-2954
Background
It has been almost three decades since the removal of oxidized proteins by the free 20S catalytic unit of the proteasome (20SPT) was proposed. Since then, experimental evidence suggesting a physiological role of proteolysis mediated by the free 20SPT has being gathered.Scope of review
Experimental data that favors the hypothesis of free 20SPT as playing a role in proteolysis are critically reviewed.Major conclusions
Protein degradation by the proteasome may proceed through multiple proteasome complexes with different requirements though the unequivocal role of the free 20SPT in cellular proteolysis towards native or oxidized proteins remains to be demonstrated.General significance
The biological significance of proteolysis mediated by the free 20SPT has been elusive since its discovery. The present review critically analyzes the available experimental data supporting the proteolytic role of the free or single capped 20SPT. 相似文献19.
Flavien Zannini Anna Moseler Raphaël Bchini Tiphaine Dhalleine Andreas J. Meyer Nicolas Rouhier Jérémy Couturier 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(2):426-436
Background
Glutaredoxins (GRXs) are oxidoreductases involved in diverse cellular processes through their capacity to reduce glutathionylated proteins and/or to coordinate iron?sulfur (Fe-S) clusters. Among class II GRXs, the plant-specific GRXS16 is a bimodular protein formed by an N-terminal endonuclease domain fused to a GRX domain containing a 158CGFS signature.Methods
The biochemical properties (redox activity, sensitivity to oxidation, pKa of cysteine residues, midpoint redox potential) of Arabidopsis thaliana GRXS16 were investigated by coupling oxidative treatments to alkylation shift assays, activity measurements and mass spectrometry analyses.Results
Activity measurements using redox-sensitive GFP2 (roGFP2) as target protein did not reveal any significant glutathione-dependent reductase activity of A. thaliana GRXS16 whereas it was able to catalyze the oxidation of roGFP2 in the presence of glutathione disulfide. Accordingly, Arabidopsis GRXS16 reacted efficiently with oxidized forms of glutathione, leading to the formation of an intramolecular disulfide between Cys158 and the semi-conserved Cys215, which has a midpoint redox potential of - 298?mV at pH?7.0 and is reduced by plastidial thioredoxins (TRXs) but not GSH. By promoting the formation of this disulfide, Cys215 modulates GRXS16 oxidoreductase activity.Conclusion
The reduction of AtGRXS16, which is mandatory for its oxidoreductase activity and the binding of Fe-S clusters, depends on light through the plastidial FTR/TRX system. Hence, disulfide formation may constitute a redox switch mechanism controlling GRXS16 function in response to day/night transition or oxidizing conditions.General significance
From the in vitro data obtained with roGFP2, one can postulate that GRXS16 would mediate protein glutathionylation/oxidation in plastids but not their deglutathionylation. 相似文献20.
V. Guru KrishnaKumar Lokesh Baweja Krittika Ralhan Sharad Gupta 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2590-2604