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1.
K. Bender R. T. Seibert T. F. Wienker V. Kren M. Pravenec S. Bissbort 《Biochemical genetics》1994,32(5-6):147-154
A genetic locus controlling the electrophoretic mobility of a methylglyoxal dehydrogenase (EC 1.2.1.23) in the rat is described. The locus, designatedMgd1, is expressed in liver and kidney. Inbred rat strains have fixed either alleleMgd1
a
or alleleMgd1
b
. Codominant expression is observed in heterozygotes, providing evidence for a tetrameric enzyme structure. Backcross progenies showed the expected 1:1 segregation ratio, and there is evidence thatMgd1 is linked toPep3 andFh1 on chromosome 13. There is also evidence for two additional methylglyoxal dehydrogenases:Mgd2, present in liver and kidney, andMgd3, present only in heart.Supported by the Deutsche Forschungsgemeinschaft (Grant Be 352/18-1). 相似文献
2.
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3.
Shuping Li Fei Gao Jiaqiang Huang Yuanyuan Wu Sen Wu Xin Gen Lei 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(11):2473-2479
Background
Selenium (Se) is an essential micronutrient required by avian species. Dietary Se/vitamin E deficiency induces three classical diseases in chicks: exudative diathesis, nutritional pancreatic atrophy, and nutritional muscular dystrophy.Scope of review
This review is to summarize and analyze the evolution, regulation, and function of avian selenogenome and selenoproteome and their relationship with the three classical Se/vitamin E deficiency diseases.Major conclusions
There are 24 selenoproteins confirmed in chicks, with two avian-specific members (SELENOU and SELENOP2) and two missing mammalian members (GPX6 and SELENOV). There are two forms of SELENOP containing 1 or 13 selenocysteine residues. In addition, a Gallus gallus gene was conjectured to be the counterpart of the human SEPHS2. Expression of selenoprotein genes in the liver, pancreas, and muscle of chicks seemed to be highly responsive to dietary Se changes. Pathogeneses of the Se/vitamin E deficient diseases in the chicks were likely produced by missing functions of selected selenoproteins in regulating cellular and tissue redox balance and inhibiting oxidative/reductive stress-induced cell death.General significance
Gene knockout models, similar to those of rodents, will help characterize the precise functions of avian selenoproteins and their comparisons with those of mammalian species. 相似文献4.
Joanna Strumillo Katarzyna E. Nowak Anita Krokosz Aleksandra Rodacka Mieczyslaw Puchala Grzegorz Bartosz 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(4):877-885
Background
Nitric oxide is a well-known gaseous signaling molecule and protein modifying agent. However, at higher concentrations or during oxidative stress nitric oxide may exert some deleterious effects on protein structure and function. Here we investigated the influence of nitric oxide and products of its oxidation on two glycolytic enzymes: GAPDH and LDH under in vitro nitrosative stress conditions. Secondly, we applied natural antioxidants: melatonin and resveratrol to examine their effects on the enzymes under studied conditions.Methods
By means of UV–VIS and fluorescence spectroscopy methods we compared nitric oxide mediated changes of enzyme activities, amount of free sulfhydryl groups (-SH) and bis-ANS probe binding. Finally, we predicted potential cysteine residues modified by nitric oxide in studied proteins using GPS-SNO software.Results
Our results indicated that nitric oxide reversibly inactivates GAPDH but does not affect the activity of LDH. Nitric oxide dependent GAPDH activity decline was accompanied by the reduction of the amount of free –SH groups and GAPDH-bound bis-ANS fluorescence. Reduction of the number of free –SH groups and protein-bound bis-ANS fluorescence was also observed in LDH treated with NO. Applied antioxidants increased inactivation of GAPDH and structural changes of GAPDH and LDH.Conclusions
Nitric oxide modifies function and structure of thiol-dependent enzyme such as GAPDH and structure of LDH which function do not rely on cysteine thiols. Both resveratrol and melatonin exerted prooxidative properties in studied conditions.General significance
Extensively studied antioxidants: resveratrol and melatonin may function as a prooxidative species under in vitro nitrosative stress conditions. 相似文献5.
Giulia Lori Tania Gamberi Paolo Paoli Anna Caselli Erica Pranzini Riccardo Marzocchini Alessandra Modesti Giovanni Raugei 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2533-2544
Background
Low Molecular Weight Phosphotyrosine Protein Phosphatase (LMW-PTP) is an enzyme involved not only in tumor onset and progression but also in type 2 diabetes. A recent review shows that LMW-PTP acts on several RTK (receptor tyrosine kinase) such as PDGFR, EGFR, EphA2, Insulin receptor. It is well described also its interaction with cSrc. It is noteworthy that most of these conclusions are based on the use of cell lines expressing low levels of LMW-PTP. The aim of the present study was to discover new LMW-PTP substrates in aggressive human tumors where the over-expression of this phosphatase is a common feature.Methods
We investigated, by proteomic analysis, the protein phosphorylation pattern of A375 human melanoma cells silenced for LMW-PTP. Two-dimensional electrophoresis (2-DE) analysis, followed by western blot was performed using anti-phosphotyrosine antibodies, in order to identify differentially phosphorylated proteins.Results
Proteomic analysis pointed out that most of the identified proteins belong to the glycolytic metabolism, such as α-enolase, pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase and triosephosphate isomerase, suggesting an involvement of LMW-PTP in glucose metabolism. Assessment of lactate production and oxygen consumption demonstrated that LMW-PTP silencing enhances glycolytic flux and slow down the oxidative metabolism. In particular, LMW-PTP expression affects PKM2 tyrosine-phosphorylation and nuclear localization, modulating its activity.Conclusion
All these findings propose that tumor cells are subjected to metabolic reprogramming after LMW-PTP silencing, enhancing glycolytic flux, probably to compensate the inhibition of mitochondrial metabolism.General significance
Our results highlight the involvement of LMW-PTP in regulating glucose metabolism in A375 melanoma cells. 相似文献6.
Garik V. Mkrtchyan Muammer Üçal Andrea Müllebner Sergiu Dumitrescu Martina Kames Rudolf Moldzio Marek Molcanyi Samuel Schaefer Adelheid Weidinger Ute Schaefer Juergen Hescheler Johanna Catharina Duvigneau Heinz Redl Victoria I. Bunik Andrey V. Kozlov 《BBA》2018,1859(9):925-931
Background and purpose
Based on the fact that traumatic brain injury is associated with mitochondrial dysfunction we aimed at localization of mitochondrial defect and attempted to correct it by thiamine.Experimental approach
Interventional controlled experimental animal study was used. Adult male Sprague-Dawley rats were subjected to lateral fluid percussion traumatic brain injury. Thiamine was administered 1?h prior to trauma; cortex was extracted for analysis 4?h and 3?d after trauma.Key results
Increased expression of inducible nitric oxide synthase (iNOS) and tumor necrosis factor receptor 1 (TNF-R1) by 4?h was accompanied by a decrease in mitochondrial respiration with glutamate but neither with pyruvate nor succinate. Assays of TCA cycle flux-limiting 2-oxoglutarate dehydrogenase complex (OGDHC) and functionally linked enzymes (glutamate dehydrogenase, glutamine synthetase, pyruvate dehydrogenase, malate dehydrogenase and malic enzyme) indicated that only OGDHC activity was decreased. Application of the OGDHC coenzyme precursor thiamine rescued the activity of OGDHC and restored mitochondrial respiration. These effects were not mediated by changes in the expression of the OGDHC sub-units (E1k and E3), suggesting post-translational mechanism of thiamine effects. By the third day after TBI, thiamine treatment also decreased expression of TNF-R1. Specific markers of unfolded protein response did not change in response to thiamine.Conclusion and implications
Our data point to OGDHC as a major site of damage in mitochondria upon traumatic brain injury, which is associated with neuroinflammation and can be corrected by thiamine. Further studies are required to evaluate the pathological impact of these findings in clinical settings. 相似文献7.
Huaidong Zhang Qin Li Lina Wang Yan Chen 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(5):1199-1208
Background
Alcohol dehydrogenases (ADHs) catalyze the reversible oxidation of alcohol using NAD+ or NADP+ as cofactor. Three ADH homologues have been identified in Komagataella phaffii GS115 (also named Pichia pastoris GS115), ADH1, ADH2 and ADH3, among which adh3 is the only gene responsible for consumption of ethanol in Komagataella phaffii GS115. However, the relationship between structure and function of mitochondrial alcohol dehydrogenase isozyme III from Komagataella phaffii GS115 (KpADH3) is still not clear yet.Methods
KpADH3 was purified, identified and characterized by multiple biophysical techniques (Nano LC-MS/MS, Enzymatic activity assay, X-ray crystallography).Results
The crystal structure of KpADH3, which was the first ADH structure from Komagataella phaffii GS115, was solved at 1.745?Å resolution. Structural analysis indicated that KpADH3 was the sole dimeric ADH structure with face-to-face orientation quaternary structure from yeast. The major structural different conformations located on residues 100–114 (the structural zinc binding loop) and residues 337–344 (the loop between α12 and β15 which covered the catalytic domain). In addition, three channels were observed in KpADH3 crystal structure, channel 2 and channel 3 may be essential for substrate specific recognition, ingress and egress, channel 1 may be the pass-through for cofactor.Conclusions
KpADH3 plays an important role in the metabolism of alcohols in Komagataella phaffii GS115, and its crystal structure is the only dimeric medium-chain ADH from yeast described so far.General significance
Knowledge of the relationship between structure and function of KpADH3 is crucial for understanding the role of KpADH3 in Komagataella phaffii GS115 mitochondrial metabolism. 相似文献8.
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9.
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10.
The aquaglyceroporin of Plasmodium falciparum (PfAQP) is a bi-functional channel with permeability for water and solutes. Its functions supposedly are in osmotic protection of parasites and in facilitation of glycerol permeation for glycerolipid biosynthesis. Here, we show PfAQP permeability for the glycolysis-related metabolites methylglyoxal, a cytotoxic byproduct, and dihydroxyacetone, a ketotriose. AQP3, the red cell aquaglyceroporin, also passed dihydroxacetone but excluded methylglyoxal. Proliferation of malaria parasites was inhibited by methylglyoxal with an IC50 around 200 μM. Surprisingly, also dihydroxyacetone, which is an energy source in human cells, was antiproliferative in chloroquine-sensitive and resistant strains with an IC50 around 3 mM. We expressed P. falciparum glyceraldehyde 3-phosphate dehydrogenase (PfGAPDH) to examine whether it is inhibited by either carbonyl compound. Methylglyoxal did not affect PfGAPDH on incubation with 2.5 mM for 20 h. Treatment with 2.5 mM dihydroxyacetone, however, abolished PfGAPDH activity within 6 h. Aquaglyceroporin permeability for glycolytic metabolites may thus be of physiological significance. 相似文献
11.
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12.
Michael G. Friedrich Zhen Wang Kevin L. Schey Roger J.W. Truscott 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(4):907-913
Background
The human body contains numerous long-lived proteins which deteriorate with age, typically by racemisation, deamidation, crosslinking and truncation. Previously we elucidated one reaction responsible for age-related crosslinking, the spontaneous formation of dehydroalanine (DHA) intermediates from phosphoserine and cysteine. This resulted in non-disulphide covalent crosslinks. The current paper outlines a novel posttranslational modification (PTM) in human proteins, which involves the addition of dehydroalanylglycine (DHAGly) to Lys residues.Methods
Human lens digests were examined by mass spectrometry for the presence of (DHA)Gly (+144.0535?Da) adducts to Lys residues. Peptide model studies were undertaken to elucidate the mechanism of formation.Results
In the lens, this PTM was detected at 18 lysine sites in 7 proteins. Using model peptides, a pathway for its formation was found to involve initial formation of the glutathione degradation product, γ-Glu(DHA)Gly from oxidised glutathione (GSSG). Once the Lys adduct formed, the Glu residue was lost in a hydrolytic mechanism apparently catalysed by the ε-amino group of the Lys.Conclusions
This discovery suggests that within cells, the functional groups of amino acids in proteins may be susceptible to modification by reactive metabolites derived from GSSG.General significance
Our finding demonstrates a novel +144.0535?Da PTM arising from the breakdown of oxidised glutathione. 相似文献13.
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14.
Selenium unmasks protective iron armor: A possible defense against cutaneous inflammation and cancer
Jack L. Arbiser Michael Y. Bonner Nicole Ward Justin Elsey Shikha Rao 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(11):2518-2527
Background
A link between selenium deficiency and inflammatory skin diseases have been noted by many, but this link is still not well understood. We have previously studied the efficacy of ceramide analogs, based on the fire ant venom Solenopsin A, against our psoriasis animal model. Treatment of animals with solenopsin analogs resulted in significantly improved skin as well as in a coordinate downregulation of selenoproteins, namely Glutathione Peroxidase 4 (GPX4). We thus hypothesize that ferroptosis may be a physiologic process that may protect the skin from both inflammatory and neoplastic processes.Methods
We analyze and compare gene expression profiles in the GEO database from clinical skin samples taken from healthy patients and psoriasis patients (both involved and noninvolved skin lesions). We validated the gene expression results against a second, independent, cohort from the GEO database.Results
Significant reduction in gene expression of GPX4, elevated expression of Nrf2 downstream targets, and expression profiles mirroring erastin-inhibition of Cystine/Glutamate Antiporter-System XC activity in psoriatic skin lesions, compared to both noninvolved skin and healthy patient samples, suggest an innately inducible mechanism of ferroptosis.Conclusions
We present data that may indicate selenoproteins, particularly GPX4, in resolving inflammation and skin cancer, including the novel hypothesis that the human organism may downregulate GPX4 and reactive oxygen (REDOX) regulating proteins in the skin as a way of resolving psoriasis and nonmelanoma skin cancer through increased reactive oxygen species. Further studies are needed to investigate ferroptosis as a possible physiologic mechanism for eliminating inflammatory and malignant tissues.General significance
This study provides a fresh framework for understanding the seemingly contradictory effects of selenium supplementation. In addition, it offers a novel explanation of how physiologic upregulation of ferroptosis and downregulation of selenoprotein synthesis may mediate resolution of inflammation and carcinogenesis. This is of therapeutic significance. 相似文献15.
Viktoria Dotz Roosmarijn F.H. Lemmers Karli R. Reiding Agnes L. Hipgrave Ederveen Aloysius G. Lieverse Monique T. Mulder Eric J.G. Sijbrands Manfred Wuhrer Mandy van Hoek 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2613-2622
Background
Little is known about enzymatic N-glycosylation in type 2 diabetes, a common posttranslational modification of proteins influencing their function and integrating genetic and environmental influences. We sought to gain insights into N-glycosylation to uncover yet unexplored pathophysiological mechanisms in type 2 diabetes.Methods
Using a high-throughput MALDI-TOF mass spectrometry method, we measured N-glycans in plasma samples of the DiaGene case-control study (1583 cases and 728 controls). Associations were investigated with logistic regression and adjusted for age, sex, body mass index, high-density lipoprotein-cholesterol, non-high-density lipoprotein-cholesterol, and smoking. Findings were replicated in a nested replication cohort of 232 cases and 108 controls.Results
Eighteen glycosylation features were significantly associated with type 2 diabetes. Fucosylation and bisection of diantennary glycans were decreased in diabetes (odds ratio (OR)?=?0.81, p?=?1.26E-03, and OR?=?0.87, p?=?2.84E-02, respectively), whereas total and, specifically, alpha2,6-linked sialylation were increased (OR?=?1.38, p?=?9.92E-07, and OR?=?1.40, p?=?5.48E-07). Alpha2,3-linked sialylation of triantennary glycans was decreased (OR?=?0.60, p?=?6.38E-11).Conclusions
While some glycosylation changes were reflective of inflammation, such as increased alpha2,6-linked sialylation, our finding of decreased alpha2,3-linked sialylation in type 2 diabetes patients is contradictory to reports on acute and chronic inflammation. Thus, it might have previously unreported immunological implications in type 2 diabetes.General significance
This study provides new insights into N-glycosylation patterns in type 2 diabetes, which can fuel studies on causal mechanisms and consequences of this complex disease. 相似文献16.
We purified a fraction that showed NAD+-linked methylglyoxal dehydrogenase activity, directly catalyzing methylglyoxal oxidation to pyruvate, which was significantly increased in glutathione-depleted Candida albicans. It also showed NADH-linked methylglyoxal-reducing activity. The fraction was identified as a NAD+-linked alcohol dehydrogenase (ADH1) through mass spectrometric analyses. In ADH1-disruptants of both the wild type and glutathione-depleted cells, the intracellular methylglyoxal concentration increased significantly; defects in growth, differentiation, and virulence were observed; and G2-phase arrest was induced. 相似文献
17.
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18.
Stella A. Child Vanessa P. Rossi Stephen G. Bell 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(2):408-417
Background
Cyp147G1 is one of 47 cytochrome P450 encoding genes in Mycobacterium marinum M, a pathogenic bacterium with a high degree of sequence similarity to Mycobacterium tuberculosis and Mycobacterium ulcerans. Cyp147G1 is one of only two of these cyp genes which are closely associated with a complete electron transfer system.Methods
The substrate range of the enzyme was tested in vitro and the activity of CYP147G1 was reconstituted in vivo by co-producing the P450 with the ferredoxin and ferredoxin reductase.Results
Substrates of CYP147G1 include fatty acids ranging from octanoic to hexadecanoic acid. CYP147G1 catalysed the selective hydroxylation of linear and ω-2 methyl branched fatty acids at the ω-1 position (≥ 98%). Oxidation of ω-1 methyl branched fatty acids generated the ω and ω-1 hydroxylation products in almost equal proportions, indicating altered position of hydrogen abstraction.Conclusions
This selectivity of fatty acid hydroxylation inferred that linear species must bind in the active site of the enzyme with the terminal methyl group sequestered so that abstraction at the CH bonds of the ω-1 position is favoured. With branched substrates, one of the methyl groups must be close to the compound I oxygen atom and enable hydroxylation at the terminal methyl group to compete with the reaction at the ω-1CH bond.General significance
Hydroxy fatty acids are widely used for industrial, food and medical purposes. CYP147G1 demonstrates high regioselectivity for hydroxylation at a sub-terminal position on a broad range of linear fatty acids, not seen in other CYP enzymes. 相似文献19.
Po-Huang Liang Wen-Ling Lin Han-Yu Hsieh Tsung-Yi Lin Chun-Hsu Chen Sunil K. Tewary Hsiao-Lin Lee Shuo-Fu Yuan Barbara Yang Jyun-Yu Yao Meng-Chiao Ho 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(3):513-521
Background
An array of glycoside hydrolases with multiple substrate specificities are required to digest plant cell wall polysaccharides. Cel5E from Clostridium thermocellum and Cel5A from Thermotoga maritima are two glycoside hydrolase family 5 (GH5) enzymes with high sequence and structural similarity, but notably possess different substrate specificities; the former is a bifunctional cellulase/xylanase and the latter is a cellulase/mannanase. A specific loop in TmCel5A, Tmloop, is one of the most structurally divergent regions compared to CtCel5E and interacts with substrates, suggesting the importance for mannan recognition.Method
A Tmloop inserted CtCel5E and its related mutants were produced to investigate the role of Tmloop in catalysis. Crystal structure of CtCel5E-TmloopF267A followed by site-direct mutagenesis reveals the mechanism. RtCelB, a homolog with Tmloop was identified to have mannanase activity.Result
Tmloop incorporation enables CtCel5E to gain mannanase activity. Tyr270, His277, and Trp282 in the Tmloop are indispensable for CtCel5E-Tmloop catalysis, and weakening hydrophobic environment near the Tmloop enhances enzyme kcat. Using our newly identified loop motif to search for structurally conserved homologs in other subfamilies of GH5, we identified RtCelB. This homolog, originally annotated as a cellulase also possesses mannanase and xylanase activities.Conclusion
Our studies show that Tmloop enhances GH5 enzyme promiscuity and plays a role in catalysis.General significance
The study identified a loop of GH5 for mannan recognition and catalysis. Weakening the hydrophobic environment near the loop can also enhance the enzyme catalytic rate. Our findings provide a new insight on mannan recognition and activity enhancement of GH5. 相似文献20.
Rani Kunjithapatham Shanmugasundaram Ganapathy-Kanniappan 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2555-2563