RESUMO
Methylglyoxal (MG) is a highly reactive aldehyde able to form covalent adducts with proteins and nucleic acids, disrupting cellular functions. In this study, we performed a screening of Saccharomyces cerevisiae (S. cerevisiae) strains to find out which genes of cells are responsive to MG, emphasizing genes against oxidative stress and DNA repair. Yeast strains were grown in the YPD-Galactose medium containing MG (0.5 to 12 mM). The tolerance to MG was evaluated by determining cellular growth and cell viability. The toxicity of MG was more pronounced in the strains with deletion in genes engaged with DNA repair checkpoint proteins, namely Rad23 and Rad50. MG also impaired the growth and viability of S. cerevisiae mutant strains Glo1 and Gsh1, both components of the glyoxalase I system. Differently, the strains with deletion in genes encoding for antioxidant enzymes were apparently resistant to MG. In summary, our data indicate that DNA repair and MG detoxification pathways are keys in the control of MG toxicity in S. cerevisiae.
Assuntos
Lactoilglutationa Liase , Proteínas de Saccharomyces cerevisiae , Reparo do DNA , Proteínas de Ligação a DNA , Lactoilglutationa Liase/genética , Lactoilglutationa Liase/metabolismo , Estresse Oxidativo , Aldeído Pirúvico/toxicidade , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genéticaRESUMO
Detoxification of methylglyoxal, a toxic by-product of central sugar metabolism, is a major issue for all forms of life. The glyoxalase pathway evolved to effectively convert methylglyoxal into d-lactate via a glutathione hemithioacetal intermediate. Recently, we have shown that the monomeric glyoxalase I from maize exhibits a symmetric fold with two cavities, potentially harboring two active sites, in analogy with homodimeric enzyme surrogates. Here we confirm that only one of the two cavities exhibits glyoxalase I activity and show that it adopts a tunnel-shaped structure upon substrate binding. Such conformational change gives rise to independent binding sites for glutathione and methylglyoxal in the same active site, with important implications for the molecular reaction mechanism, which has been a matter of debate for several decades. DATABASE: Structural data are available in The Protein Data Bank database under the accession numbers 6BNN, 6BNX, and 6BNZ.
Assuntos
Lactoilglutationa Liase/química , Substâncias Macromoleculares/química , Conformação Proteica , Zea mays/enzimologia , Sequência de Aminoácidos/genética , Domínio Catalítico/genética , Lactoilglutationa Liase/genética , Lactoilglutationa Liase/ultraestrutura , Substâncias Macromoleculares/ultraestrutura , Dobramento de Proteína , Aldeído Pirúvico/química , Especificidade por Substrato , Açúcares/metabolismoRESUMO
The glyoxalase system is ubiquitous among all forms of life owing to its central role in relieving the cell from the accumulation of methylglyoxal, a toxic metabolic byproduct. In higher plants, this system is upregulated under diverse metabolic stress conditions, such as in the defence response to infection by pathogenic microorganisms. Despite their proven fundamental role in metabolic stresses, plant glyoxalases have been poorly studied. In this work, glyoxalase I from Zea mays has been characterized both biochemically and structurally, thus reporting the first atomic model of a glyoxalase I available from plants. The results indicate that this enzyme comprises a single polypeptide with two structurally similar domains, giving rise to two lateral concavities, one of which harbours a functional nickel(II)-binding active site. The putative function of the remaining cryptic active site remains to be determined.
Assuntos
Lactoilglutationa Liase/química , Zea mays/química , Zea mays/enzimologia , Sequência de Aminoácidos , Domínio Catalítico , Clonagem Molecular , Cristalografia por Raios X , Lactoilglutationa Liase/genética , Lactoilglutationa Liase/metabolismo , Modelos Moleculares , Dados de Sequência Molecular , Níquel/metabolismo , Conformação Proteica , Alinhamento de Sequência , Zea mays/genética , Zea mays/metabolismoRESUMO
The glyoxalase system plays an important role in various physiological processes in plants, including salt stress tolerance. We report the effects of overexpressing glyoxalase I and glyoxalase II genes in transgenic tomato (Solanum lycopersicum Mill.) cv. Ailsa Craig. Stable expression of both transgenes was detected in the transformed tomato plants under salt stress. The transgenic lines overexpressing GlyI and GlyII under a high NaCl concentration (800 mM) showed reduced lipid peroxidation and the production of H2O2 in leaf tissues. A greater decrease in the chlorophyll a+b content in wild-type (WT) compared with transgenic lines was also observed. These results suggest that the over expression of two genes, GlyI and GlyII, may enhance salt stress tolerance by decreasing oxidative stress in transformed tomato plants. This work will help our understanding of the putative role of the glyoxalase system in the tolerance to abiotic stress in tomato plants.
Assuntos
Lactoilglutationa Liase/metabolismo , Folhas de Planta/enzimologia , Plantas Geneticamente Modificadas/enzimologia , Tolerância ao Sal/genética , Tioléster Hidrolases/metabolismo , Secas , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Lactoilglutationa Liase/genética , Solanum lycopersicum/genética , Solanum lycopersicum/fisiologia , Estresse Oxidativo , Cloreto de Sódio/farmacologia , Estresse Fisiológico , Tioléster Hidrolases/genéticaRESUMO
Breast cancer is the neoplasia with the highest incidence in women worldwide. Proteomics approaches have accelerated the discovery of diagnostic and prognostic biomarkers. Here, we compared the proteomic profiles of breast tumors versus non-tumoral tissues in order to identify modulated proteins, which could represent potential markers associated to clinical features. By two-dimensional electrophoresis, we detected 28 differentially expressed proteins. Among these, 21 proteins were up-regulated and 7 were down-regulated in tumors (p<0.05). Proteins were identified using LC/ESI-MS/MS tandem mass spectrometry. One protein was identified as glyoxalase 1 (GLO1), an enzyme involved in detoxification of methylglyoxal, a cytotoxic product of glycolysis. GLO1 overexpression was confirmed by western blot assays in paired normal and tumor breast tissues in clinical stages I-III, and by immunohistochemistry on tissue microarrays (TMA) comprising a cohort of 98 breast tumors and 20 healthy specimens. Results from TMA demonstrated that GLO1 is overexpressed in 79% of tumors. Interestingly, GLO1 up-regulation correlates with advanced tumor grade (p<0.05). These findings demonstrate the association of GLO1 overexpression with tumor grade and pointed out for additional studies to establish the importance of GLO1 in breast cancer.
Assuntos
Neoplasias da Mama/enzimologia , Carcinoma Ductal de Mama/enzimologia , Expressão Gênica , Lactoilglutationa Liase/metabolismo , Proteoma/metabolismo , Idoso de 80 Anos ou mais , Sequência de Aminoácidos , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/patologia , Estudos de Casos e Controles , Linhagem Celular Tumoral , Eletroforese em Gel Bidimensional , Feminino , Humanos , Lactoilglutationa Liase/genética , Pessoa de Meia-Idade , Dados de Sequência Molecular , Gradação de Tumores , Fragmentos de Peptídeos/química , Proteômica , Análise Serial de TecidosRESUMO
Autism is a generalized or pervasive developmental disorder that affects about five in ten thousand children worldwide (5/10.000). In Maracaibo the incidence is 1.1/1000, with a ratio of male/female, 4:1. The autistic disorder is defined entirely based on the impairment in three areas: 1) Impairment of social interaction, 2) Impairment in communication and 3) Stereotyped and repetitive behavior. Autism is a disorder with a large genetic component and a oligogenic inheritance model has been proposed. Quantitative and qualitative disturbances of certain components of the immune system in patients with autism have been used as endophenotype, one of the strategies used to identify candidate genes for susceptibility to autism. On the other hand the hypersensitivity to specific groups of foods such as casein and gluten has become clear, which has led to the postulation of immunogenetics theories in autism, which mainly involve genes of the histocompatibility major complex. Although it has not been confirmed that immunogenetics factors could be involved in the etiopathogenesis of autism, several studies have shown the influence of the complex Human Leucocyte Antigen (HLA) HLA DR4, DR13, DR11, A2 and others genes in the clinical status, risk and therapeutic response of some psychiatric disorders. The lack of literature demands a greater number of studies related to different ethnic groups and the participation of HLA, as well as the importance of this complex in the pathogenesis of psychiatric illness.
Assuntos
Transtorno Autístico/genética , Transtorno Autístico/imunologia , Animais , Transtorno Autístico/epidemiologia , Transtorno Autístico/etiologia , Citocinas/sangue , Citocinas/imunologia , Modelos Animais de Doenças , Feminino , Hipersensibilidade Alimentar , Frequência do Gene , Ligação Genética , Predisposição Genética para Doença , Antígenos HLA/genética , Antígenos HLA/imunologia , Humanos , Fenômenos Imunogenéticos , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Subunidade alfa2 de Receptor de Interleucina-13/genética , Lactoilglutationa Liase/genética , Complexo Principal de Histocompatibilidade , Masculino , Camundongos , Camundongos Knockout , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-met , Receptores de Fatores de Crescimento/genéticaRESUMO
Eight enzyme gene markers were studied in a sample of Piaroa Indians of Venezuela. ADA, DIA, PGD and AK markers seemed to be non-polymorphic whereas the following markers were found to be polymorphic: ACP1, where the only common electrophoretic alleles present were ACP1*A and ACP1*B (.955); ESD (ESD*1 = .781); PGM1 (PGM1*1 = .736) for which the subtypes (PGM1*1S = .546; PGM1*1F = .190; PGM1*2S = .140; PGM1*2F = .124) were also tested, and GLO1 (GLO1*1 = .347). Some showed a certain heterogeneity in distribution within the Piaroa population. The Piaroa Indians turned out to be different from other ethnic groups living in the same territory.
Assuntos
Carboxilesterase , Eritrócitos/enzimologia , Indígenas Sul-Americanos/genética , Fosfatase Ácida/genética , Hidrolases de Éster Carboxílico/genética , Feminino , Frequência do Gene , Humanos , Lactoilglutationa Liase/genética , Masculino , Fosfoglucomutase/genética , Polimorfismo Genético , VenezuelaRESUMO
No association between GLO and Hp was found in three Brazilian samples (153 Whites, 216 Blacks from Porto Alegre and 564 mixed individuals from Aracaju). In a sample of 174 Blacks (settled along the Trombetas river) a moderate (p less than 0.02) association was found, but not of the same kind as that observed by other authors. Population stratification instead of interactions in fitness may explain our findings.
Assuntos
Haptoglobinas/genética , Lactoilglutationa Liase/genética , Liases/genética , População Negra , Brasil , Frequência do Gene , Humanos , Lactoilglutationa Liase/sangue , População BrancaAssuntos
Aberrações Cromossômicas/imunologia , Cromossomos Humanos 6-12 e X , Proteínas do Sistema Complemento/genética , Complexo Principal de Histocompatibilidade , Sarcoidose/imunologia , Adolescente , Aberrações Cromossômicas/genética , Transtornos Cromossômicos , Humanos , Lactoilglutationa Liase/genética , Masculino , Recombinação Genética , Sarcoidose/genéticaRESUMO
Genetic polymorphism of red cell enzymes glutamate-pyruvate transaminase (GPT) and glyoxalase I (GLO) was investigated in five villages of the Colombian Andes. The GPT1 and GLO1 gene frequencies show a considerable range, but compatible to the range of European populations. In both the systems there is slight excess of observed homozygosity suggesting that the infrastructure of the subpopulations may be influenced by inbreeding.