Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.5.1.18 (glutathione S-transferase)
22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Laminin binding protein precursor p40 (LBP-p40) was long believed to be located exclusively in the cytoplasm. We recently reported localization of epitope-tagged LBP-p40 to the nucleus tightly associated with nuclear structure as well as on ribosomes. In this paper, we analyze the interaction of LBP-p40 with DNA and nuclear proteins in vitro. LBP-p40 was found to bind to a double-stranded DNA cellulose column at moderate salt. However, when mixed with a high salt nuclear extract, LBP-p40 was eluted from the DNA cellulose column only at higher salt. An LBP-p40 affinity column indicated that both histone H1 and in particular the core histones associate with LBP-p40. Using recombinant core histone molecules fused with glutathione S-transferase (GST), we demonstrate that histones H2A, H2B, and H4 are capable of interacting with LBP-p40, whereas H3 is not. These results suggest that association of LBP-p40 with histones H2A, H2B, and H4 confers tight binding of LBP-p40 to chromatin DNA in the nucleus.
...
PMID:LBP-p40 binds DNA tightly through associations with histones H2A, H2B, and H4. 987 28

Based on partial amino acid sequences of p50 purified from a high-salt buffer extract of a rat liver nuclear matrix fraction, p50 cDNA was cloned and sequenced, and its amino acid sequence was predicted. The sequence contained helicase motifs, and showed homology with RuvB DNA helicase of Thermus thermophilus and an open reading frame for an unknown 50.5 k protein of Saccharomyces cerevisiae. p50 was expressed as a GST-fusion protein and antiserum against the protein was generated. p50 was localized to the nuclear matrix by cell fractionation and immunoblotting. p50 bound to ATP-Sepharose beads. Ultracentrifugation and gel filtration analyses showed that p50 in rat liver and Xenopus egg mitotic extracts exists as large complexes corresponding to 697 k and 447 k, respectively. A 50 k protein reactive with p50 antibodies was detected not only in rat liver nuclei, but also in a Xenopus egg cytoplasm fraction and a S. cerevisiae extract. This suggests that this putative DNA helicase is present in a wide variety of species ranging from yeast to mammals.
...
PMID:Molecular shape and ATP binding activity of rat p50, a putative mammalian homologue of RuvB DNA helicase. 1005 36

The Rho GDP dissociation inhibitor (GDI) is an ubiquitously expressed regulatory protein involved in the cycling of Rho proteins between membrane-bound and soluble forms. Here, we characterized the Rho solubilization activity of a glutathione S-transferase (GST) - GDI fusion protein in a cell-free system derived from rat kidney. Addition of GST-GDI to kidney brush border membranes resulted in the specific release of Cdc42 and RhoA from the membranes, while RhoB and Ras were not extracted. The release of Cdc42 and RhoA by GST-GDI was dose dependent and saturable with about 50% of both RhoA and Cdc42 extracted. The unextracted Rho proteins were tightly bound to membranes and could not be solubilized by repeated GST-GDI treatment. These results demonstrated that kidney brush border membranes contained two populations of RhoA and Cdc42. Furthermore, the GST-GDI solubilizing activity on membrane-bound Cdc42 and RhoA was abolished at physiological conditions of salt and temperature in all tissues examined. When using bead-immobilized GST-GDI, KCl did not reduced the binding of Rho proteins. However, washing brush border membranes with KCl prior treatment by GST-GDI inhibited the extraction of Rho proteins. Taken together, these results suggest that the binding of GDI to membrane-bound Cdc42 and RhoA occurs easily under physiological ionic strength conditions, but a complementary factor is required to extract these proteins from membranes. These observations suggest that the shuttling activity of GDI upon Rho proteins could be normally downregulated under physiological conditions.
...
PMID:Regulation of Rho protein binding to membranes by rhoGDI: inhibition of releasing activity by physiological ionic conditions. 1042 87

In this article we present two 1000 ps molecular dynamics simulations on the rat micro-glutathione S-transferase dimeric enzyme in complex with the product 1-(S-glutathionyl)-2,4-dinitrobenzene, in a periodic box with explicit solvent molecules, and investigate the effect of long-range electrostatics models on the structure and dynamics of the dimer and its components. One simulation used the standard cutoff method (10A), whilst the other used the particle-mesh Ewald (PME) method. We monitored the root mean-square atomic deviation (RMSD) from the initial crystal structure to examine the convergence of both simulations, as well as several other structural parameters such as the distance between active sites, rigid body rotation between domains in subunits, radius of gyration, B-factors, number of hydrogen bonds and salt bridges and solvent-accessible surface area. For example, with the PME method, the dimer structure remains much closer to the initial crystallographic structure with an average RMSD of 1.3A +/- 0.1A and 1.0A +/- 0.1A for all heavy and backbone atoms, respectively, in the last 200 ps; the respective values for the cutoff simulation are 4.7A +/- 0.3A and 4.2A +/- 0.3A. The large deviations observed in the cutoff simulation severely affected the stability of the enzyme dimer and its complex with the bound product. This finding is contrary to that found in a similar study of the monomeric protein ubiquitin [Fox, T. & Kollman, P. A. Proteins Struct. Func. Genet. 25, 315-334 (1996)]. Unlike the earlier published work, the present study provides evidence that the standard cutoff method is not generally valid for the study of protein complexes, or their subunits.
...
PMID:Molecular dynamics simulations of a protein-protein dimer: particle-mesh Ewald electrostatic model yields far superior results to standard cutoff model. 1044 4

We have used three kinds of stresses, including the signaling compound jasmonic acid, an environmental stressor, UV irradiation, and a heavy metal salt copper chloride, to study changes in the protein patterns in rice (Oryza sativa L.) leaf tissues using two-dimensional polyacrylamide gel electrophoresis. However, instead of using lysis buffer containing urea (O'Farrell, J. Biol. Chem. 1975, 250, 4007-4021) for extraction of proteins from rice seedling tissues, we used Tris-HCl buffer (commonly used for extraction of proteins for separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) for extraction of proteins and resolved these extracted proteins by the usual method of O'Farrell. Furthermore, the induction of a large number of proteins was clearly observed over controls. No spots corresponding to these induced proteins were found in the control experiment, indicating qualitative changes in protein patterns after various stress treatments. A total of 12 out of 13 proteins could be N-terminally sequenced from jasmonic acid-treated rice leaf tissues, and one protein was sequenced from UV-irradiated leaf tissues. These proteins showed high homology to pathogenesis-related (thaumatin-like protein, a PR5 class protein; a beta-1,3-glucanase precursor; an intracellular PR protein encoded by PBZ1 gene, and an antifungal protein) and cellular protectant (glutathione transferase, EC 2.5.1.18; and ascorbate peroxidase) proteins, from plants, including rice. Results presented here suggest a role for jasmonic acid in the self-defense mechanisms of rice plants.
...
PMID:Separation of proteins from stressed rice (Oryza sativa L.) leaf tissues by two-dimensional polyacrylamide gel electrophoresis: induction of pathogenesis-related and cellular protectant proteins by jasmonic acid, UV irradiation and copper chloride. 1060 17

Dictyostelium discoideum myosin Ik (MyoK) is a novel type of myosin distinguished by a remarkable architecture. MyoK is related to class I myosins but lacks a cargo-binding tail domain and carries an insertion in a surface loop suggested to modulate motor velocity. This insertion shows similarity to a secondary actin-binding site present in the tail of some class I myosins, and indeed a GST-loop construct binds actin. Probably as a consequence, binding of MyoK to actin was not only ATP- but also salt-dependent. Moreover, as both binding sites reside within its motor domain and carry potential sites of regulation, MyoK might represent a new form of actin crosslinker. MyoK was distributed in the cytoplasm with a significant enrichment in dynamic regions of the cortex. Absence of MyoK resulted in a drop of cortical tension whereas overexpression led to significantly increased tension. Absence and overexpression of MyoK dramatically affected the cortical actin cytoskeleton and resulted in reduced initial rates of phagocytosis. Cells lacking MyoK showed excessive ruffling, mostly in the form of large lamellipodia, accompanied by a thicker basal actin cortex. At early stages of development, aggregation of myoK null cells was slowed due to reduced motility. Altogether, the data indicate a distinctive role for MyoK in the maintenance and dynamics of the cell cortex.
...
PMID:Dictyostelium myosin IK is involved in the maintenance of cortical tension and affects motility and phagocytosis. 1065 55

The effects of DOCA-salt hypertensive treatment on hepatic glutathione-dependent defense system, antioxidant enzymes, lipid peroxidation, mixed function oxidase and UDP-glucuronyl transferase activities were investigated in male Sprague Dawley rats. Compared with controls, DOCA-salt hypertensive rats had lower body weights (linked to liver hypertrophy). Mixed function oxidase and p-nitrophenol-UGT activities were not affected by the treatment but a significant lower rate of the glucuronoconjugation rate of bilirubin (p < 0.001) was observed in DOCA-salt hypertensive rats. While cytosolic glutathione contents and glutathione reductase activity were not affected, glutathione peroxidase (p < 0.001), glutathione transferase (p < 0.001) and catalase (p < 0.01) activities were decreased and associated with higher malondialdehyde contents (p < 0.001) in treated rats. The imbalance in liver antioxidant status (increasing generation of cellular radical species), associated with increases in lipid peroxidation, suggests that oxidative stress might be directly related to arterial hypertension in DOCA-salt treated male Sprague Dawley rats.
...
PMID:Antioxidant status, lipid peroxidation, mixed function oxidase and UDP-glucuronyl transferase activities in livers from control and DOCA-salt hypertensive male Sprague Dawley rats. 1072 30

We have shown previously that the solvent-induced equilibrium unfolding mechanism of class Sigma glutathione S-transferase (GST) is strongly affected by ionic strength [Stevens, Hornby, Armstrong and Dirr (1998) Biochemistry 37, 15534-15541]. The protein is dimeric and has a hydrophilic subunit interface. Here we show that ionic strength alone has significant effects on the conformation of the protein, in particular at the active site. With the use of NaCl at up to 2 M under equilibrium conditions, the protein lost 60% of its catalytic activity and the single tryptophan residue per subunit became partly exposed. The effect was independent of protein concentration, eliminating the dissociation of the dimer as a possibility for the conformational changes. This was confirmed by size-exclusion HPLC. There was no significant change in the secondary structure of the protein according to far-UV CD data. Manual-mixing and stopped-flow kinetics experiments showed a slow single-exponential salt-induced change in protein fluorescence. For equilibrium and kinetics experiments, the addition of an active-site ligand (S-hexylglutathione) completely protected the protein from the ionic-strength-induced conformational changes. This suggests that the change occurs at or near the active site. Possible structural reasons for these novel effects are proposed, such as the flexibility of the alpha-helix 2 region as well as the hydrophilic subunit interface, highlighting the importance of electrostatic interactions in maintaining the structure of the active site of this GST.
...
PMID:Electrostatic interactions affecting the active site of class sigma glutathione S-transferase. 1072 18

S-Crystallin from octopus lens has a tertiary structure similar to sigma-class glutathione transferase (GST). However, after isolation from the lenses, S-crystallin was found to aggregate more easily than sigma-GST. In vitro experiments showed that the lens S-crystallin can be polymerized and finally denatured at increasing concentration of urea or guanidinium chloride (GdmCl). In the intermediate concentrations of urea or GdmCl, the polymerized form of S-crystallin is aggregated, as manifested by the increase in light scattering and precipitation of the protein. There is a delay time for the initiation of polymerization. Both the delay time and rate of polymerization depend on the protein concentration. The native protein showed a maximum fluorescence emission spectrum at 341 nm. The GdmCl-denatured protein exhibited two fluorescence maxima at 310 nm and 358 nm, respectively, whereas the urea-denatured protein showed a fluorescence peak at 358 nm with a small peak at 310 nm. The fluorescence intensity was quenched. Monomers, dimers, trimers, and polymers of the native protein were observed by negative-stain electron microscopic analysis. The aggregated form, however, showed irregular structure. The aggregate was solubilized in high concentrations of urea or GdmCl. The redissolved denatured protein showed an identical fluorescence spectrum to the protein solution that was directly denatured with high concentrations of urea or GdmCl. The denatured protein was readily refolded to its native state by diluting with buffer solution. The fluorescence spectrum of the renatured protein solution was similar to that of the native form. The phase diagrams for the S-crystallin in urea and GdmCl were constructed. Both salt concentration and pH value of the solution affect the polymerization rate, suggesting the participation of ionic interactions in the polymerization. Comparison of the molecular models of the S-crystallin and sigma-GST suggests that an extra ion-pair between Asp-101 and Arg-14 in S-crystallin contributes to stabilizing the protomer. Furthermore, the molecular surface of S-crystallin has a protruding Lys-208 on one side and a complementary patch of aspartate residues (Asp-90, Asp-94, Asp-101, Asp-102, Asp-179, and Asp-180) on the other side. We propose a molecular model for the S-crystallin polymer in vivo, which involves side-by-side associations of Lys-208 from one protomer and the aspartate patch from another protomer that allows the formation of a polymeric structure spontaneously into a liquid crystal structure in the lens.
...
PMID:Molecular basis for the polymerization of octopus lens S-crystallin. 1073 85

Incubation of human whole blood for 24 h at 37 degrees C in the presence of 100-400 microg/dl lead chloride or lead acetate caused a concentration-dependent decrease in the level of reduced glutathione up to 40%. Similarly, the activities of glutathione reductase, glutathione peroxidase and glutathione S-transferase were decreased up to 25%, 50%, and 19%, respectively. Moreover, 100 microg/dl lead chloride or lead acetate slowed the process of glutathione regeneration, and delayed the time for complete regeneration from 20 to 40 min. When glutathione S-transferase was purified by affinity chromatography on Sepharose-linked glutathione, incubated with lead chloride or lead acetate, a concentration-dependent inhibition of the enzymatic activity was observed reaching 50% inhibition at a lead salt concentration of 6000 microg/dl.
...
PMID:Effect of lead concentration on the level of glutathione, glutathione S-transferase, reductase and peroxidase in human blood. 1080 41


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---