共查询到20条相似文献，搜索用时 31 毫秒
1.
Objective
To establish a method for the recovery and reutilization of hydroxypropyl-β-cyclodextrin (HP-β-CD) to lower the cost of its industrial application in cortisone acetate bioconversion.Results
HP-β-CD is not degraded by Arthrobacter simplex CPCC140451 (ASP) resting cells and 96.4 % HP-β-CD could be recovered by isobutyl acetate extraction. Moreover, the inclusion ability of recovered HP-β-CD barely decreased. The saccharide metabolic and catalytic activities of ASP were greater in the aqueous phase after extracting with isobutyl acetate than other organic solvents. Cyclic utilization tests showed that cortisone acetate conversion ratio was 91.0 % after eight cycles and reached 95.7 % with 0.2–0.6 mM HP-β-CD. Furthermore, >90 % conversion ratio was reached per cycle through a co-cyclic-utilization method with HP-β-CD and immobilized ASP.Conclusion
Cortisone acetate conversion ratio in the HP-β-CD cyclic-utilization method is promising for industrial applications. The method can also be expanded to other CDs and other hydrophobic compounds bioconversion.2.
Rajshri Singh Priya Dagar Shyama Pal Bhakti Basu Bhavani S. Shankar 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(3):669-683
Background
Tumor microenvironment is composed of a largely altered extracellular matrix with different cell types. The complex interplay between macrophages and tumor cells through several soluble factors and signaling is an important factor in breast cancer progression.Methods
We have extended our earlier studies on monocyte and macrophage conditioned medium (M?CM) and have carried out proteomic analysis to identify its constituents as well as validation. The 8-gene signature identified through macrophage-breast cancer cell interactions was queried in cBioportal for bioinformatic analyses.Results
Proteomic analysis (MALDI-TOF and LC-MS/MS) revealed integrin and matrix metalloproteinases in M?CM which activated TGF-β1, IL-6, TGF- βRII and EGFR as well as its downstream STAT and SMAD signaling in breast cancer cells. Neutralization of pro-inflammatory cytokines (TNF-α. Il-1β, IL-6) abrogated the M?CM induced migration but invasion to lesser extent. The 8- gene signature identified by macrophage-tumor interactions (TNF-α, IL-1β, IL-6, MMP1, MMP9, TGF-β1, TGF-βRII, EGFR) significantly co-occurred with TP53 mutation, WTAPP1 deletion and SLC12A5 amplification along with differential expression of PSAT1 and ESR1 at the mRNA level and TPD52and PRKCD at the protein level in TCGA (cBioportal). Together these genes form a novel 15 gene signature which is altered in 63.6% of TCGA (1105 samples) data and was associated with high risk and poor survival (p < 0.05) in many breast cancer datasets (SurvExpress).Conclusions
These results highlight the importance of macrophage signaling in breast cancer and the prognostic role of the15-gene signature.General significance
Our study may facilitate novel prognostic markers based on tumor-macrophage interaction. 相似文献3.
Bruno César Feltes Conrado Pedebos Diego Bonatto Hugo Verli 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2579-2589
Background
Xeroderma Pigmentosum (XP) is a disease caused by mutations in the nucleotide excision repair (NER) pathway. Patients with XP exhibit a high propensity to skin cancers and some subtypes of XP can even present neurological impairments. During NER, DDB2 (XPE), in complex with DDB1 (DDB-Complex), performs the DNA lesion recognition. However, not much is known about how mutations found in XP patients affect the DDB2 structure and complex assembly. Thus, we searched for structural evidence associated with the role of three naturally occurring mutations found in XPE patients: R273H, K244E, and L350P.Methods
Each mutant was individually constructed and submitted to multiple molecular dynamics simulations, done in triplicate for each designed system. Additionally, Dynamic Residue Interaction Networks were designed for each system and analyzed parallel with the simulations.Results
DDB2 mutations promoted loss of flexibility in the overall protein structure, producing a different conformational behavior in comparison to the WT, especially in the region comprising residues 354 to 371. Furthermore, the DDB-complex containing the mutated forms of DDB2 showed distinct behaviors for each mutant: R273H displayed higher structural instability when complexed; L350P affected DDB1 protein-protein binding with DDB2; and K244E, altered the complex binding trough different ways than L350P.Conclusions
The data gathered throughout the analyses helps to enlighten the structural basis for how naturally occurring mutations found in XPE patients impact on DDB2 and DDB1 function.General significance
Our data influence not only on the knowledge of XP but on the DNA repair mechanisms of NER itself. 相似文献4.
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5.
Alessandro Marengo Stefania Forciniti Ilaria Dando Elisa Dalla Pozza Barbara Stella Nicolas Tsapis Najet Yagoubi Giuseppina Fanelli Elias Fattal Christopher Heeschen Marta Palmieri Silvia Arpicco 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(1):61-72
Background
Pancreatic cancer stem cells (CSCs) are responsible for resistance to standard therapy, metastatic potential, and disease relapse following treatments. The current therapy for pancreatic ductal adenocarcinoma (PDAC) preferentially targets the more differentiated cancer cell population, leaving CSCs as a cell source for tumor mass formation and recurrence. For this reason, there is an urgent need to improve current therapies and develop novel CSC-targeted therapeutic approaches.Methods
Hyaluronic acid (HA) decorated liposomes, containing diethyldithiocarbamate?copper (Cu(DDC)2), able to target the specific CSC marker CD44 receptor were prepared by ion gradient technique and fully characterized. Their antiproliferative effect was evaluated on pancreatic CSCs derived from PDAC cell lines or patients. To clarify the mechanism of action of Cu(DDC)2 liposomes, ROS level neutralization assay in the presence of N-acetyl-L-cysteine was performed.Results
Liposomes showed high encapsulation efficiency and Cryo-TEM analysis revealed the presence of Cu(DDC)2 crystals in the aqueous core of liposomes. In vitro test on pancreatic CSCs derived from PDAC cell lines or patients showed high ROS mediated anticancer activity of HA decorated liposomes. The sphere formation capability of CSCs obtained from patients was drastically reduced by liposomal formulations containing Cu(DDC)2.Conclusions
The obtained results show that the encapsulation of Cu(DDC)2 complex in HA decorated liposomes strongly increases its anti-proliferative activity on pancreatic CSCs.General significance
This paper describes for the first time the use of HA decorated liposomes containing Cu(DDC)2 against pancreatic CSCs and opens the way to the development of nanomedicine based CSC-targeted therapeutic approaches. 相似文献6.
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7.
8.
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9.
Sophie Winkler Rupert Derler Bernd Gesslbauer Elmar Krieger Andreas J. Kungl 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(3):528-533
Background
Binding of chemokines to glycosaminoglycans (GAGs) is a crucial step in leukocyte recruitment to inflamed tissues.Methods
A disaccharide compositional analysis of the HS dp6 fraction in combination with MS analysis of the CCL2-depleted dp6 fraction was the basis for target GAG ligand structure suggestions. Four experimentally-derived heparan sulfate hexasaccharides, two potentially chemokine-specific and two unspecific, have been docked to CCL2. Subsequent 300?ns molecular dynamics simulations were used to improve the docked complexes.Results
Hexasaccharides with four sulfations and no acetylations are suggested for selective and high affinity chemokine binding. Using the Antithromin-III/heparin complex as positive control for docking, we were able to recover the correct complex structure only if the previously liganded ATIII structure was used as input. Since the liganded structure is not known for a CCL2-GAG complex, we investigated if molecular dynamics simulations could improve initial docking results. We found that all four GAG oligosaccharides ended up in close contact with the known binding residues after about 100?ns simulation time.Conclusions
A discrimination of specific vs. unspecific CCL2 GAG ligands is not possible by this approach. Long-time molecular dynamics simulations are, however, well suited to capture the delicate enthalpy/entropy balance of GAG binding and improve results obtained from docking.General significance
With the comparison of two methods, MS-based ligand identification and molecular modelling, we have shown the current limitations of our molecular understanding of complex ligand binding which is could be due to the numerical inaccessibility of ligand-induced protein conformational changes. 相似文献10.
Vincenzo Maione Francesca Cantini Mirko Severi Lucia Banci 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(9):1980-1987
Background
The CIA2A protein, in complex with CIAO1, has been proposed to be exclusively implicated in the maturation of cytosolic aconitase. However, how the CIA2A-CIAO1 complex generates active aconitase is still unknown and the available structural information has not provided any crucial insights into the molecular function of CIA2A.Methods
In this work we have characterized the Fe/S cluster binding properties of CIA2A and of the CIA2A-CIAO1 complex via NMR, UV???vis absorption and EPR spectroscopies and we have investigated how the Fe/S cluster is transferred to inactive aconitase/IRP1 protein.Results
We found that an heterotrimeric species formed by two molecules of CIA2A and one of CIAO1 can bind one [4Fe-4S] cluster and that residue Cys90 of CIA2A is one of the cluster ligand. The holo trimeric complex is able to transfer the [4Fe-4S] cluster to apo-IRP1 thus generating the active form of aconitase.Conclusions and general significance
These findings, which highlight a functional role for CIA2A-CIAO1 complex in aconitase maturation, raises a broad interest and can have a high impact on the community studying metal trafficking and iron?sulfur protein biogenesis. The present study can provide solid bases for further investigation of the molecular mechanisms involving also other CIA machinery proteins. 相似文献11.
Afsaneh Sadremomtaz Kamran Mansouri Golnaz Alemzadeh Majid Safa Ahmadreza Esmaeili Rastaghi S. Mohsen Asghari 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2688-2700
Background
Neutralization of vascular endothelial growth factor receptor 1 (VEGFR1) and/or VEGFR2 is a widely used means of inhibiting tumor angiogenesis.Methods
Based on the complex X-ray structures of VEGFA/VEGFR1, VEGFA/VEGFR2, and VEGFB/VEGFR1, a peptide (referred to as VGB) was designed to simultaneously bind to VEGFR1 and VEGFR2, and binding, antiangiogenic and antitumor properties of the peptide was investigated in vitro.Results
VGB bound to both VEGFR1 and VEGFR2 in human umbilical vein endothelial cells (HUVECs) and 4?T1 mammary carcinoma tumor (MCT) cells, and inhibited the proliferation of HUVE, 4?T1 MCT, and U87 glioblastoma cells. Through abrogation of AKT and ERK1/2 phosphorylation, VEGFA-stimulated proliferation, migration, and two- and three-dimensional tube formation in HUVECs were inhibited more potently by VGB than by bevacizumab. In a murine 4?T1 MCT model, VGB strongly inhibited tumor growth without causing weight loss, accompanied by inhibition of AKT and ERK1/2 phosphorylation, a significant decrease in tumor cell proliferation (Ki-67 expression), angiogenesis (CD31 and CD34 expression), an increase in apoptosis index (increased TUNEL staining and p53 expression and decreased Bcl-2 expression), and the suppression of systematic spreading of the tumor (reduced NF-κB and MMP-9 and increased E-cadherin expression).Conclusion
The dual specificity of VGB for VEGFR1 and VEGFR2, through which the PI3K/AKT and MAPK/ERK1/2 signaling pathways can be abrogated and, subsequently, angiogenesis, tumor growth, and metastasis are inhibited.General significance
This study demonstrated that simultaneous blockade of VEGFR1 and VEGFR2 downstream cascades is an effective means for treatment of various angiogenic disorders, especially cancer. 相似文献12.
Luigi Servillo Domenico Castaldo Alfonso Giovane Rosario Casale Nunzia D&#x;Onofrio Domenico Cautela Maria Luisa Balestrieri 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(4):991-998
Background
Ophthalmic acid (OPH), γ-glutamyl-L-2-aminobutyryl-glycine, a tripeptide analogue of glutathione (GSH), has recently captured considerable attention as a biomarker of oxidative stress in animals. The OPH and GSH biosynthesis, as well as some biochemical behaviors, are very similar. Here, we sought to investigate the presence of OPH in plants and its possible relationship with GSH, known to possess multiple functions in the plant development, growth and response to environmental changes.Methods
HPLC-ESI-MS/MS analysis was used to examine the occurrence of OPH in leaves from various plant species, and flours from several plant seeds. Different types of oxidative stress, i.e., water, dark, paraquat, and cadmium stress, were induced in rye, barley, oat, and winter wheat leaves to evaluate the effects on the levels of OPH and its metabolic precursors.Results
OPH and its dipeptide precursor, γ-glutamyl-2-aminobutyric acid, were found to occur in phylogenetically distant plants. Interestingly, the levels of OPH were tightly associated with the oxidative stress tested. Levels of OPH precursors, γ-glutamyl-2-aminobutyric acid and 2-aminobutyric acid, the latter efficiently formed in plants via biosynthetic pathways absent in the animal kingdom, were also found to increase during oxidative stress.Conclusions
OPH occurs in plants and its levels are tightly associated with oxidative stress.General significance
OPH behaves as an oxidative stress marker and its biogenesis might occur through a biochemical pathway common to many living organisms. 相似文献13.
Thorsten Saenger Stefan Vordenbäumen Swetlana Genich Samer Haidar Marten Schulte Christian Nienberg Ellen Bleck Matthias Schneider Joachim Jose 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(3):632-643
Background
The milk protein αS1-casein was recently reported to induce secretion of proinflammatory cytokines via Toll-like receptor 4 (TLR4). In this study, αS1-casein was identified as binder of theTLR4 ecto domain.Methods
IL-8 secretion after stimulation of TLR4/MD2 (myeloid differentiation factor 2)/CD14 (cluster of differentiation 14)-transfected HEK293 cells (TLR4+) and Mono Mac 6 cells (MM6) with recombinant αS1-casein, or LPS as control was monitored. Binding of αS1-casein to TLR4 was quantified by microscale thermophoresis (MST).Results
αS1-casein induced secretion of IL-8 in TLR4+ cells and in MM6 cells with a six-times higher final IL-8 concentration in supernatants. IL-8 secretion was inhibited by intracellular TLR4-domain antagonist TAK-242 with an IC50-value of 259.6?nM, by ecto-domain TLR4 antagonistic mianserin with 10–51?μM and by anti-CD14-IgA. The binding constants (KD) of αS1-casein to the TLR4, MD2, and CD14 were 2.8?μM, 0.3?μM and 2.7?μM, respectively. Finally, αS1-casein showed a higher affinity to TLR4/MD2 (KD: 2.2?μM) compared to LPS (KD: 8.2?μM).Conclusion
Human αS1-casein induced proinflammatory effects are dependent upon binding to the TLR4 ectodomain and the presence of CD14. αS1-casein displayed stronger TLR4 agonistic activity than LPS via a different mode of action.General significance
Breast milk protein αS1-casein is a proinflammatory cytokine. 相似文献14.
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15.
Fábio F. Cardoso Rafael J. Borges Thiago R. Dreyer Guilherme H.M. Salvador Walter L.G. Cavalcante Maeli Dal Pai Márcia Gallacci Marcos R.M. Fontes 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2728-2737
Background
Specific compounds found in vegetal species have been demonstrated to be efficient inhibitors of snake toxins, such as phospholipase A2-like (PLA2-like) proteins. These particular proteins, present in several species of vipers (Viperidae), induce a severe local myotoxic effect in prey and human victims, and this effect is often not efficiently neutralized by the regular serum therapy. PLA2-like proteins have been functionally and structurally studied since the early 1990s; however, a comprehensive molecular mechanism was proposed only recently.Methods
Myographic and histological techniques were used to evaluate the inhibitory effect of chicoric acid (CA) against BthTX-I myotoxin. Isothermal titration calorimetry assays were used to measure the affinity between the inhibitor and the toxin. X-ray crystallography was used to reveal details of this interaction.Results
CA prevented the blockade of indirectly evoked muscle contraction and inhibited muscle damage induced by BthTX-I. The inhibitor binds to the toxin with the highest affinity measured for a natural compound in calorimetric assays. The crystal structure and molecular dynamics simulations demonstrated that CA binds at the entrance of the hydrophobic channel of the toxin and binds to one of the clusters that participates in membrane disruption.Conclusions
CA prevents the myotoxic activity of the toxin, preventing its activation by simultaneous binding with two critical regions.General significance
CA is a potential myotoxic inhibitor to other PLA2-like proteins and a possible candidate to complement serum therapy. 相似文献16.
Sarah Caughlin Shikhar Maheshwari Yuksel Agca Cansu Agca Aaron J. Harris Kristina Jurcic Ken K.-C. Yeung David F. Cechetto Shawn N. Whitehead 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(6):1327-1338
Background
Accumulation of simple gangliosides GM2 and GM3, and gangliosides with longer long-chain bases (d20:1) have been linked to toxicity and the pathogenesis of Alzheimer's disease (AD). Conversely, complex gangliosides, such as GM1, have been shown to be neuroprotective. Recent evidence using matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS) has demonstrated that a-series gangliosides are differentially altered during normal aging, yet it remains unclear how simple species are shifting relative to complex gangliosides in the prodromal stages of AD.Methods
Ganglioside profiles in wild-type (Wt) and transgenic APP21 Fischer rats were detected and quantified using MALDI-IMS at P0 (birth), 3, 12, and 20?months of age and each species quantified to allow for individual species comparisons.Results
Tg APP21 rats were found to have a decreased level of complex gangliosides in a number of brain regions as compared to Wt rats and showed higher levels of simple gangliosides. A unique pattern of expression was observed in the white matter as compared to gray matter regions, with an age-dependent decrease in GD1 d18:1 species observed and significantly elevated levels of GM3 in Tg APP21 rats.Conclusions
These results are indicative of a pathological shift in ganglioside homeostasis during aging that is exacerbated in Tg APP21 rats.General significance
Ganglioside dysregulation may occur in the prodromal stages of neurodegenerative diseases like AD. 相似文献17.
Prashanth Kumar Koochana Abhinav Mohanty Suman Das Biswamaitree Subhadarshanee Suresh Satpati Anshuman Dixit Surendra Chandra Sabat Rabindra K. Behera 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(5):1190-1198
Background
Ferritin detoxifies excess of free Fe(II) and concentrates it in the form of ferrihydrite (Fe2O3·xH2O) mineral. When in need, ferritin iron is released for cellular metabolic activities. However, the low solubility of Fe(III) at neutral pH, its encapsulation by stable protein nanocage and presence of dissolved O2 limits in vitro ferritin iron release.Methods
Physiological reducing agent, NADH (E1/2?=??330?mV) was inefficient in releasing the ferritin iron (E1/2?=?+183?mV), when used alone. Thus, current work investigates the role of low concentration (5–50?μM) of phenazine based electron transfer (ET) mediators such as FMN, PYO - a redox active virulence factor secreted by Pseudomonas aeruginosa and PMS towards iron mobilization from recombinant frog M ferritin.Results
The presence of dissolved O2, resulting in initial lag phase and low iron release in FMN, had little impact in case of PMS and PYO, reflecting their better ET relay ability that facilitates iron mobilization. The molecular modeling as well as fluorescence studies provided further structural insight towards interaction of redox mediators on ferritin surface for electron relay.Conclusions
Reductive mobilization of iron from ferritin is dependent on the relative rate of NADH oxidation, dissolved O2 consumption and mineral core reduction, which in turn depends on E1/2 of these mediators and their interaction with ferritin.General significance
The current mechanism of in vitro iron mobilization from ferritin by using redox mediators involves different ET steps, which may help to understand the iron release pathway in vivo and to check microbial growth. 相似文献18.
Hyeonjun Kim Hyejin Kim Jeong K. Lee 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2674-2687
Background
Protoporphyrin IX (PPn), an intermediate in the heme biosynthesis reaction, generates singlet oxygen upon exposure to UV light. It has been proposed that PPn is channeled directly to ferrochelatase within a protoporphyrinogen dehydrogenase (PgdH1)-protoporphyrin ferrochelatase (PpfC) complex as a way to avoid this damaging side reaction. However, the PgdH1-PpfC complex has not been characterized, and the question of how heme affects the activities of PgdH1 has not been addressed.Methods
Protein interactions were explored through pull-down assays and western blotting, and the importance of this complex in vivo was examined using inter-species combinations of the two proteins. The purified PgdH1-PpfC complex was characterized kinetically and used for heme binding studies.Results
In Vibrio vulnificus, PgdH1 and PpfC formed an 8:8 heterohexadecameric complex that was important for maintaining PPn at low levels. PpfC catalyzed PPn efficiently whether or not it was part of the complex. Notably, heme was a noncompetitive inhibitor of V. vulnificus PgdH1, but a competitive inhibitor of the human protoporphyrinogen oxidase PgoX.Conclusion
The PdgH1-PpfC complex is important for protective channeling of PPn and for efficient catalysis of free PPn. The production of PPn by PgdH1 is regulated by feedback inhibition by heme.General significance
Both proteobacteria and eukaryotes have evolved mechanisms to prevent the harmful accumulation of the heme biosynthesis intermediate PPn. The data presented here suggest two previously unknown mechanisms: the channeling of PPn through the PgdH1-PpfC complex, and the direct inhibition of PgdH1 activity (PgoX activity as well) by heme. 相似文献19.
Maria-Armineh Tossounian Inge Van Molle Khadija Wahni Silke Jacques Kris Gevaert Frank Van Breusegem Didier Vertommen David Young Leonardo Astolfi Rosado Joris Messens 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(3):775-789
Background
Glutathione transferases play an important role as detoxifying enzymes. In A. thaliana, elevated levels of reactive oxygen species (ROS), provoked during biotic and abiotic stress, influence the activity of GSTU23. The aim of this study is to determine the impact of oxidative stress on the function and structure of GSTU23.Methods
The impact of oxidation on the function of GSTU23 was studied using a glutathione transferase biochemical assay and mass spectrometry. With kinetics, circular dichroism and thermodynamics, we compared reduced with oxidized GSTU23. X-ray crystal structures of GSTU23 visualize the impact of oxidation on methionines and cysteines.Results
In the presence of 100 μM H2O2, oxidation of the methionine side-chain to a sulfoxide is the prominent post-translational modification, which can be reduced by C. diphtheriae MsrA and MsrB. However, increasing the level to 200 μM H2O2 results in a reversible intramolecular disulfide between Cys65-Cys110, which is substrate for glutaredoxin. Under these oxidizing conditions, GSTU23 undergoes a structural change and forms a more favourable enzyme-substrate complex to overcome kcat decrease.Conclusions and significance
At lower H2O2 levels (100 μM), GSTU23 forms methionine sulfoxides. Specifically, oxidation of Met14, located near the catalytic Ser13, could interfere with both GSH binding and catalytic activation. At higher H2O2 levels (200 μM), the Cys65-Cys110 disulfide bond protects other cysteines and also methionines from overoxidation. This study shows the impact of oxidative stress on GSTU23 regulated by methionine sulfoxide reductases and glutaredoxin, and the mechanisms involved in maintaining its catalytic functionality under oxidizing conditions. 相似文献20.
Manel B. Hammouda Ichrak Riahi-Chebbi Soumaya Souid Houcemeddine Othman Zohra Aloui Najet Srairi-Abid Habib Karoui Ammar Gasmi Edith M. Magnenat Timothy N.C. Wells Kenneth J. Clemetson José Neptuno Rodríguez-López Khadija Essafi-Benkhadir 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(3):600-614