Primary and secondary structural analyses of glutathione S-transferase π from human placenta

Ahmad, Hassan; Wilson, Douglas E.; Fritz, Richard R.; Singh, Shivendra V.; Medh, Rheem D.; Nagle, Gregg T.; Awasthi, Yogesh C.; Kurosky, Alexander

doi:10.1016/0003-9861(90)90277-6

Cited by 106 publications

(43 citation statements)

References 34 publications

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“…The cytosolic GSTs have been subdivided into at least 13 distinct evolutionary classes designated Alpha, Mu, Pi, Theta, Sigma, Zeta, Kappa, Omega, Phi, Tau, Delta, Epsilon, and Beta on the basis of their primary structure, immunological properties, and substrate specificities (3,(12)(13)(14)(15)(16)(17)(18)(19). GSTs possess a high specificity for glutathione as the nucleophile but exhibit broad specificity with regard to structurally diverse electrophilic second substrates.…”

mentioning

confidence: 99%

An Electron-sharing Network Involved in the Catalytic Mechanism Is Functionally Conserved in Different Glutathione Transferase Classes

Winayanuwattikun¹,

Ketterman

2005

Journal of Biological Chemistry

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In Anopheles dirus glutathione transferase D3-3, there are electrostatic interactions between the negatively charged glutamyl ␣-carboxylate group of glutathione, the positively charged Arg-66, and the negatively charged Asp-100. This ionic interaction is stabilized by a network of hydrogen bonds from Ser-65, Thr-158, Thr-162, and a conserved water-mediated contact. This alternating ionic bridge interaction between negatively and positively charged residues stabilized by a network of hydrogen bonding we have named an electron-sharing network. We show that the electron-sharing network assists the glutamyl ␣-carboxylate of glutathione to function as a catalytic base accepting the proton from the thiol group forming an anionic glutathione, which is a crucial step in the glutathione transferase (GST) catalysis. Kinetic studies demonstrate that the mutation of electron-sharing network residues results in a decreased ability to lower the pK a of the thiol group of glutathione. Although the residues that contribute to the electron-sharing network are not conserved in the primary sequence, structural characterizations indicate that the presence of the network can be mapped to the same region in all GST classes. A structural diversification but functional conservation suggests a significant role for the electron-sharing network in catalysis as the purpose was maintained during the divergent evolution of GSTs. This network appears to be a functionally conserved motif that contributes to the "base-assisted deprotonation" model suggested to be essential for the glutathione ionization step of the catalytic mechanism.

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confidence: 99%

An Electron-sharing Network Involved in the Catalytic Mechanism Is Functionally Conserved in Different Glutathione Transferase Classes

Winayanuwattikun¹,

Ketterman

2005

Journal of Biological Chemistry

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“…Amino acid sequence analyses of GST Pi proteins isolated from human placenta have indicated the existence of at least two variant GST Pi proteins, one with Ile and the other with Val at codon 104 (27). Despite these findings, the complete GST Pi cDNA and gene isolated by different laboratories (23)(24)(25)(26) have been identical, both in nucleotide sequence and in the sequence of the encoded peptide.…”

Section: Discussionmentioning

confidence: 99%

“…One of the placental tissues examined in this study expressed hGSTP1*B exclusively. In a prior report (27), a GST Pi protein was isolated from human placenta and shown to have the same amino acid sequence as that encoded by hGSTP1*B. However, because neither the gene encoding this GST Pi peptide nor the cDNA corresponding to its mRNA had been identified, it was inconclusive as to whether this protein was the result of a point mutation in the GST Pi gene or represented a naturally occurring polymorphism of the GST Pi gene.…”

Section: Discussionmentioning

confidence: 99%

“…The isolation of two different GST Pi proteins from human placenta (27), however, strongly indicates that genetic polymorphism may exist in the human GST Pi gene locus. In the present study, we describe the isolation and molecular characterization of full-length cDNAs of three polymorphic GST Pi genes that are expressed in human malignant glioma cells and in other normal cells and tissues.…”

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confidence: 99%

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Molecular Cloning, Characterization, and Expression in Escherichia coli of Full-length cDNAs of Three Human Glutathione S-Transferase Pi Gene Variants

Ali‐Osman

Akande

Antoun

et al. 1997

Journal of Biological Chemistry

624

450

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We report the isolation of three full-length cDNAs corresponding to the mRNAs of closely related glutathione S-transferase (GST) Pi genes, designated hGSTP1*A, hGSTP1*B, and hGSTP1*C, expressed in normal cells and malignant gliomas. The variant cDNAs result from A 3 G and C 3 T transitions at nucleotides ؉313 and ؉341, respectively. The transitions changed codon 104 from ATC (Ile) in hGSTP1*A to GTC (Val) in hGSTP1*B and hGSTP1*C and changed codon 113 from GCG (Ala) to GTG (Val) in hGSTP1*C. Both amino changes are in the electrophile-binding active site of the GST Pi peptide. Computer modeling of the deduced crystal structures of the encoded peptides showed significant deviations in the interatomic distances of critical electrophile-binding active site amino acids as a consequence of the amino acid changes. The encoded proteins expressed in Escherichia coli and purified by GSH affinity chromatography showed a 3-fold lower K m (CDNB) and a 3-4-fold higher K cat /K m for the hGSTP1*A encoded protein than the proteins encoded by hGSTP1*B and hGSTP1*C. Analysis of 75 cases showed the relative frequency of hGSTP1*C to be 4-fold higher in malignant gliomas than in normal tissues. These data provide conclusive molecular evidence of allelopolymorphism of the human GST Pi gene locus, resulting in active, functionally different GST Pi proteins, and should facilitate studies of the role of this gene in xenobiotic metabolism, cancer, and other human diseases.

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“…These alleles are common, and GSTT1 and GSTM1 null genotypes occur in f10% to 20% and 50% of the Caucasian population, respectively (13). The GSTP1 exon 5 A to G Ile 105 Val polymorphism is one of several variants reported for this locus (14,15), and the Val-containing isoform was shown to have altered specific activity and decreased heat stability (16)(17)(18).…”

Section: Introductionmentioning

confidence: 99%

A Systematic Approach to Analysing Gene-Gene Interactions: Polymorphisms at the Microsomal Epoxide Hydrolase EPHX and Glutathione S-transferase GSTM1, GSTT1, and GSTP1 Loci and Breast Cancer Risk

Spurdle

Chang

Byrnes

et al. 2007

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Objective: We undertook a case-control study in an Australian Caucasian population-based sample of 1,246 cases and 664 controls to assess the roles of detoxification gene polymorphisms EPHX T>C Tyr 113 His, GSTT1 deletion, GSTM1 deletion, and GSTP1 A>G Ile 105 Val on risk of breast cancer. Methods: We systematically addressed the main effects and possible gene-gene interactions using unconditional logistic regression to estimate odds ratios (OR) adjusted for potential confounders and using standard model building approaches based on likelihood theory. Results: There was a decreased risk associated with the EPHX CC genotype [OR, 0.60; 95% confidence interval (95% CI), 0.43-0.84; P = 0.003], marginally significant evidence of increased risk with GSTM1 null genotype (OR, 1.21; 95% CI, 1.00-1.47; P = 0.05), but no association with GSTT1 null genotype (OR, 1.12; 95% CI, 0.86-1.45; P = 0.4) or GSTP1 (OR, 0.95; 95% CI, 0.82-1.10; P = 0.5) genotype. The full model with all interactions gave a significantly better fit than a maineffects-only model (P < 0.001), providing evidence for genegene interactions. The most parsimonious model included main effects for EPHX, GSTT1, and GSTM1; a two-way interaction between EPHX and GSTM1; and a three-way interaction between EPHX, GSTM1, and GSTT1. Predicted risks were greatest for women carrying deletions of both GSTT1 and GSTM1, with either the EPHX TC genotype (OR, 2.02; 95% CI, 1.19-3.45; P = 0.009) or EPHX CC genotype (OR, 3.54; 95% CI, 1.29-9.72; P = 0.14). Conclusion: Detoxification gene polymorphisms may interact with each other to result in small groups of individuals at modestly increased risk. We caution against overinterpretation and suggest that pooling of similarly large studies is needed to clarify the possible role of such complex genegene interactions on breast cancer risk. (Cancer Epidemiol Biomarkers Prev 2007;16(4):769 -74)

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Primary and secondary structural analyses of glutathione S-transferase π from human placenta

Cited by 106 publications

References 34 publications

An Electron-sharing Network Involved in the Catalytic Mechanism Is Functionally Conserved in Different Glutathione Transferase Classes

An Electron-sharing Network Involved in the Catalytic Mechanism Is Functionally Conserved in Different Glutathione Transferase Classes

Molecular Cloning, Characterization, and Expression in Escherichia coli of Full-length cDNAs of Three Human Glutathione S-Transferase Pi Gene Variants

A Systematic Approach to Analysing Gene-Gene Interactions: Polymorphisms at the Microsomal Epoxide Hydrolase EPHX and Glutathione S-transferase GSTM1, GSTT1, and GSTP1 Loci and Breast Cancer Risk

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