Five Decades with Glutathione and the GSTome

Abstract

Uncle Folke inspired me to become a biochemist by demonstrating electrophoresis experiments on butterfly hemolymph in his kitchen. Glutathione became the subject for my undergraduate project in 1964 and has remained a focal point in my research owing to its multifarious roles in the cell. Since the 1960s, the multiple forms of glutathione transferase (GST), the GSTome, were isolated and characterized, some of which were discovered in our laboratory. Products of oxidative processes were found to be natural GST substrates. Examples of toxic compounds against which particular GSTs provide protection include 4-hydroxynonenal and ortho-quinones, with possible links to the etiology of Alzheimer and Parkinson diseases and other degenerative conditions. The role of thioltransferase and glutathione reductase in the cellular reduction of disulfides and other oxidized forms of thiols was clarified. Glyoxalase I catalyzes still another glutathione-dependent detoxication reaction. The unusual steady-state kinetics of this zinc-containing enzyme initiated model discrimination by regression analysis. Functional properties of the enzymes have been altered by stochastic mutations based on DNA shuffling and rationally tailored by structure-based redesign. We found it useful to represent promiscuous enzymes by vectors or points in multidimensional substrate-activity space and visualize them by multivariate analysis. Adopting the concept “molecular quasi-species,” we describe clusters of functionally related enzyme variants that may emerge in natural as well as directed evolution.

Emerging Regulatory Paradigms in Glutathione Metabolism

“…Glutathione transferases (GST) conjugate the tripeptide via its thiol group to endogenous and exogenous electrophilic compounds (Hayes et al, 2005; Mannervik, 2012; Townsend and Tew, 2003), reducing their reactivity and facilitating their clearance from the cell via members of the multidrug resistance associated protein family (Bachhawat et al, 2013). A comprehensive review of this topic can be found in this volume.…”

Characterization of a Phanerochaete chrysosporium Glutathione Transferase Reveals a Novel Structural and Functional Class with Ligandin Properties

“…Most GSTs are dimeric proteins. Each monomer is composed of a conserved thioredoxin domain containing the GSH binding pocket (G site) and a more variable ␣-helical domain (H site) containing the binding site for the GSH acceptor substrate (2). Most studies have focused on the GSH-dependent catalytic activities involved both in detoxification processes and endogenous metabolism.…”

Quantification of bindings of organometallic ruthenium complexes to GSTπ by mass spectrometry

“…To address the inconsistence of the binding affinity to the crucial residue (Cys48) and the inhibitory activity against GSTπ of the ruthenium complexes, we constructed the molecular models of the ruthenated GSTπ complexes with {(η 6 -arene)Ru(en)} moieties binding to Cys15 or Cys48 using the Sybyl X 1.1 program. As shown in Figs S7, the bindings of the three complexes to Cys15 and Cys48 remarkably alter the conformation of the G-site, which functions to anchor the substrate GSH of the enzyme [35,36], and all residues around the ruthenation sites are more or less shifted relative to their original position in non-bound GSTπ. Based on the constructed molecular models, the shift distances of the Cα atoms or the centres of the five/sixmembered rings in the residues nearby the binding sites were measured and are listed in Table 2.…”

“…The GSTπ enzyme in vivo is in complexation with GSH [35] which may compete with GSTπ for binding to ruthenium via Ru-S coordination [25]. Therefore, we also determined the ruthenation ratios of GSTπ in complexation with GSH by the three ruthenium arene complexes.…”