Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The three-dimensional structure of human class pi glutathione S-transferase from placenta (hGSTP1-1), a homodimeric enzyme, has been solved by Patterson search methods and refined at 2.8 A resolution to a final crystallographic R-factor of 19.6% (8.0 to 2.8 A resolution). Subunit folding topology, subunit overall structure and subunit association closely resembles the structure of porcine class pi glutathione S-transferase. The binding site of a competitive inhibitor, S-hexylglutathione, is analyzed and the locations of the binding regions for glutathione (G-site) and electrophilic substrates (H-site) are determined. The specific interactions between protein and the inhibitor's glutathione peptide are the same as those observed between glutathione sulfonate and the porcine isozyme. The H-site is located adjacent to the G-site, with the hexyl moiety lying above a segment (residues 8 to 10) connecting strand beta 1 and helix alpha A where it is in hydrophobic contact with Tyr7, Phe8, Val10, Val35 and Tyr106. Catalytic models are discussed on the basis of the molecular structure.
J Mol Biol 1992 Sep 05
PMID:Three-dimensional structure of class pi glutathione S-transferase from human placenta in complex with S-hexylglutathione at 2.8 A resolution. 152 86

Increased expression of certain glutathione S-transferase (GST) isoenzymes has frequently been associated with the development of resistance to alkylating agents and other classes of antineoplastic drugs in drug-selected cell lines. The question arises whether this phenomenon is causal or is a stress-induced response associated with drug resistance in these cell lines. We have constructed mammalian expression vectors containing the human GST mu and GST alpha 2 (Ha2) cDNAs and stably transfected them into the human breast cancer cell line MCF-7. Whereas the parental and pSV2neo-transfected cell lines display low GST activity, three individual transfected clones were identified in each group that expressed either GST mu or GST alpha 2. The range of GST activities was similar to those observed in cells selected for anticancer drug resistance. The GST mu specific activities were 56, 150, and 340 mlU/mg, compared with 10 mlU/mg of endogenous GST mu in control lines. Specific activities in GST alpha 2-transfected clones were 17, 28, and 52 mlU/mg, compared with no detectable alpha class GST in control lines. These clonal lines and the parental and pSV2neo-transfected control lines were tested for sensitivity to antineoplastic agents and other cytotoxic compounds. The clones with the highest activity in each group were 1.7-fold (GST alpha 2) to 2.1-fold (GST mu) resistant to the toxic effects of ethacrynic acid, a known substrate for GSTs. However, the GST-transfected cell lines were not resistant to doxorubicin, L-phenylalanine mustard, bis(2-chloroethyl)-1-nitrosourea, cisplatin, chlorambucil, or the GST substrates 1-chloro-2,4-dinitrobenzene or tert-butyl hydroperoxide. Thus, although L-phenylalanine mustard, bis(2-chloroethyl)-1-nitrosourea, chlorambucil, tert-butyl hydroperoxide, and 1-chloro-2,4-dinitrobenzene are known to be metabolized by glutathione-dependent GST-catalyzed reactions, there was no protection against any of these agents in MCF-7 cell lines overexpressing GST mu or GST alpha 2. We conclude that, at the levels of GST obtained in this transfection model system, overexpression of GST mu or GST alpha 2 is not by itself sufficient to confer resistance to these anticancer agents. These studies do not exclude the possibility that GST may be a marker of drug resistance or that other gene products not expressed in MCF-7 cells might cooperate with GST to confer drug resistance.
Mol Pharmacol 1992 Feb
PMID:Expression of human mu or alpha class glutathione S-transferases in stably transfected human MCF-7 breast cancer cells: effect on cellular sensitivity to cytotoxic agents. 153 4

An enzyme-linked immunosorbent assay (ELISA) has been developed for the detection of anticentromere autoantibodies in sera of patients with suspected or manifest rheumatic diseases. The antigen source used in this assay consists of the recombinant protein of glutathione S-transferase (GST) fused to the last 60 C-terminal amino acid residues of the major centromere protein CENP-B. Although this CENP-B segment is only a small part of the complete polypeptide, we show that it constitutes an important autoimmune antigenic domain which is recognized by all patient sera in which ACA can be detected using the immunoblotting technique with a HeLa S3 nuclear protein extract as antigen source.
Mol Biol Rep 1992 Feb
PMID:Molecular cloning of a major CENP-B epitope and its use for the detection of anticentromere autoantibodies. 154 84

Crystals of the recombinant 28 kDa glutathione S-transferase from Schistosoma mansoni have been obtained by the hanging-drop method of vapor diffusion from ammonium sulfate solutions. The successful crystallization of this enzyme required the presence of a reducing agent and S-hexylglutathione. The crystals belong to the cubic space group P4(1)32 (or P4(3)32), with unit cell dimensions a = 122.6 A and contain one molecule in the asymmetric unit. The crystals diffract to at least 2.8 A resolution and are suitable for X-ray crystallographic structure analysis.
J Mol Biol 1992 Mar 20
PMID:Crystallization and preliminary X-ray diffraction studies of a protective cloned 28 kDa glutathione S-transferase from Schistosoma mansoni. 156 Apr 66

A chlorambucil (CLB)-resistant cell line, N50-4, was developed from the established mouse fibroblast cell line NIH 3T3, by multistep drug selection. The mutant cells exhibited greater than 10-fold resistance to CLB. Alterations in GSH and glutathione S-transferase (GST) were found in CLB-resistant variants. A 7-10-fold increase in cellular GSH content and a 3-fold increase in GST activity were detected in N50-4 cells, compared with parental cells, as determined by enzymatic assays. An increase in steady state levels of the GST-alpha isozyme mRNA was found in the CLB-resistant cells, as analyzed by Northern blotting. No GST gene amplification or rearrangement was shown by Southern blot analysis. To test the relative roles of GSH and GST in CLB resistance, a number of GSH- and GST-blocking agents were used. The CLB toxicity was significantly enhanced in N50-4 cells by administration of either the GSH-depleting agent buthionine sulfoximine or the GST inhibitors ethacrynic acid or indomethacin. The resistance to CLB cytotoxicity in N50-4 cells, however, was still significantly higher than that of parental cells. The resistance of N50-4 cells to CLB was almost completely abolished by combination pretreatment yielding both GSH depletion and GST inhibition. The results indicate that both increased cellular GSH content and increased GST activity play major roles in CLB resistance in N50-4 mutant cells.
Mol Pharmacol 1992 Apr
PMID:Role of glutathione and glutathione S-transferase in chlorambucil resistance. 2234 62

Ascorbic acid (AH2) is a potential scavenger of superoxide radical and singlet oxygen. In the guinea pig, marginal AH2 deficiency results in intracellular oxidative damage in the cardiac tissue as evidenced by lipid peroxidation, formation of fluorescent pigment and loss of structural integrity of the microsomal membranes. The oxidative damage does not occur due to lack of enzymatic scavengers of reactive oxygen species such as superoxide dismutase, catalase and glutathione peroxidase. Also, glutathione transferase activity is not decreased in AH2 deficiency. Lipid peroxidation, fluorescent pigment formation and protein modification disappear after AH2 therapy. These results, if extra-polated to human beings, would indicate that chronic subclinical AH2 deficiency may result in progressive oxidative damage which in the long run may lead to permanent degenerative diseases in the heart.
Mol Cell Biochem 1992 Apr
PMID:Protective role of ascorbic acid against lipid peroxidation and myocardial injury. 158 41

The aim of this study was to compare the antigenicity and the immunogenicity of five constructs of a peptide, including the peptide in single copy, a tandem repeat containing three copies, a copolymer with glutaraldehyde and two constructs based on the MAP (Multiple Antigenic Peptide) model, one containing two copies (MAP-2) and the other, eight copies of the peptide (MAP-8). The peptide used in this test was the 115-131 sequence derived from the rSm28-GST antigen of Schistosoma mansoni. All constructs were recognized by rSm28-GST specific antibodies in solid phase immunoassays. However, the binding was higher when the MAP-8 was used as antigen at least partly because of its better coating on the microtiter plates. In vitro lymphoproliferative assays showed that polymer was mitogenic, repeat and MAP-2 did not stimulate rSm28-GST specific T cells while MAP-8 induced a slight response. The injection of MAP-8 to rats led to important antibody and T cell responses higher than those obtained with the other constructs. The IgG2a (cytotoxic antibody in schistosomiasis)/IgG2c (blocking antibody) ratio was independent of the immunogen. Taken together these results demonstrate that both the antigenicity and the immunogenicity of a peptide containing T and B cell epitope(s) are strongly related to the molecular form whereby it is presented and that the MAP-8 construct can be useful in serodiagnosis or in vaccination trials using synthetic peptides.
Mol Immunol 1992 Jun
PMID:Analysis of antigenicity and immunogenicity of five different chemically defined constructs of a peptide. 160 96

HepG2 cells were cultured in the presence of different concentrations of cyclosporin A (CsA) or Nva2-cyclosporin (Nva2-Cs) for up to 20 days. At a low concentration (2 micrograms/ml) of CsA or Nva2-Cs, the [3H]thymidine incorporation into DNA and the rate of incorporation of [3H]leucine into total protein decreased by 20-25%. Concentrations of 10 micrograms/ml resulted in a 70% reduction of the [3H]thymidine incorporation in comparison with controls. Low concentrations of CsA resulted in mitochondria in the condensed state together with autophagosomes, large vacuoles, and elevated numbers of coated vesicles, as shown by electron microscopy. Low concentrations of Nva2-Cs resulted in swollen mitochondria, increased autophagocytosis, and increased numbers of intermediate filaments and microtubules. Higher doses of these substances (5 micrograms/ml) caused disarrangement of mitochondrial cristae, vesiculation of the endoplasmic reticulum, an elevated number of free polysomes, and accelerated autophagocytosis. Labeling of phospholipids and triglycerides with [3H]glycerol and of cholesterol and dolichol with [3H]acetate was decreased after exposure of HepG2 cells to CsA, or, in particular, Nva2-Cs. Phospholipids secreted from the cells into the medium exhibited an increased level of labeling, but the specific radioactivity of the neutral lipids in the medium was significantly decreased. Treatment of HepG2 cells with either CsA or Nva2-Cs doubled the mitochondrial cytochrome oxidase and carnitine acetyl-transferase, as well as microsomal NADPH-cytochrome c reductase activities. Such treatment also increased the cyanide-insensitive beta-oxidation of fatty acids in peroxisomes, as well as cytoplasmic DT-diaphorase and glutathione transferase activities. Prolonged treatment of the cells with CsA did not result in any cumulative effect. HepG2 cells appear to be suitable for studying the effects of cyclosporins on cellular structure and metabolism and in this system the two drugs studied here exhibited similar effects.
Exp Mol Pathol 1991 Jun
PMID:Modulation of metabolism in HepG2 cells upon treatment with cyclosporin A and Nva2-cyclosporin. 164 68

The glutathione transferase mu gene (GST1) and the debrisoquine hydroxylase gene (CYP2D6) are known to be polymorphic in the human population and have been associated with increased susceptibility to cancer. Smokers with low lymphocyte GST mu activity are at higher risk for lung cancer, while low debrisoquine hydroxylase activity has been correlated with lower risk for lung and bladder cancer. Phenotypic characterization of these polymorphisms by lymphocyte enzyme activity (GST) and urine metabolite ratios (debrisoquine) is cumbersome for population studies. Recent cloning and sequencing of the mutant alleles of these genes has allowed genotyping via the polymerase chain reaction (PCR). Advantages of PCR approaches are speed, technical simplicity, and minimal sample requirements. This article reviews the PCR-based methods for detection of genetic polymorphisms in human cancer susceptibility genes.
Environ Mol Mutagen 1991
PMID:Detection of DNA sequence polymorphisms in carcinogen metabolism genes by polymerase chain reaction. 168 53

Restriction analysis of mitochondrial DNA (mtDNA) of 3065 humans from 62 geographic samples identified 149 haplotypes and 81 polymorphic sites. These data were used to test several aspects of the evolutionary past of the human species. A dendrogram depicting the genetic relatedness of all haplotypes shows that the native African populations have the greatest diversity and, consistent with evidence from a variety of sources, suggests an African origin for our species. The data also indicate that two individuals drawn at random from the entire sample will differ at approximately 0.4% of their mtDNA nucleotide sites, which is somewhat higher than previous estimates. Human mtDNA also exhibits more interpopulation heterogeneity (GST = 0.351 +/- 0.025) than does nuclear DNA (GST = 0.12). Moreover, the virtual absence of intermediate levels of linkage disequilibrium between pairs of sites is consistent with the absence of genetic recombination and places constraints on the rate of mutation. Tests of the selective neutrality of mtDNA variation, including the Ewens-Watterson and Tajima tests, indicate a departure in the direction consistent with purifying selection, but this departure is more likely due to the rapid growth of the human population and the geographic heterogeneity of the variation. The lack of a good fit to neutrality poses problems for the estimation of times of coalescence from human mtDNA data.
J Mol Evol 1991 Dec
PMID:The structure of human mitochondrial DNA variation. 168 53


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