Cytosolic Glutathione S-transferase in Bacteria: A Review

Abstract

Cytosolic glutathione S-transferase in bacteria possesses the biochemical capacity to degrade various classes of organochlorine pollutants in the environment in addition to their primary role of defending the organism from a wide range of endobiotics and xenobiotic substrates. Furthermore, the ability of different classes of cGST to recognize a wide repertoire of substrates due the variability in the substrate binding site of the enzymes makes them well suited for bioremediation purposes. cGSTs act as dehalogenases promoting a rapid degradation of various organochlorine compounds. Dehalogenation served as the primary mechanism for detoxification of various organochlorine compounds, making them vulnerable to attack by other degradative enzymes. However, despite their potential and advantage of wide substrate specificity, cGSTs have not been exploited for bioremediation purposes. In this review, we described the various cGST classes in bacteria and their phylogenetic relationships. Furthermore, the review reiterated that cGSTs in bacteria are involved in dehalogenation reaction, and this property can be harnessed for bioremediation of a diverse class of organochlorine pollutants as they currently represent the largest class of pollutants in the environment.

First in vivo Evidence That Glutathione-S-Transferase Operates in Photo-Oxidative Stress in Cyanobacteria

“…The currently recognized classes of cytosolic GSTs are: alpha, beta, delta, epsilon, zeta, theta, lambda (Lallement et al, 2014), mu, nu, pi, sigma, tau, phi, and omega (for review, see Oakley, 2011). More recently, others GST classes were described in bacteria: nu, zeta, and eta (for review, see Shehu et al, 2018) and in cyanobacteria: chi (Wiktelius and Stenberg, 2007; Pandey et al, 2015) and rho (Pandey et al, 2017). The mitochondrial GSTs share an evolutionary pattern with the cytosolic GSTs but differ from them by their structure and their subcellular localization (Morel and Aninat, 2011).…”

Stress-Based Production, and Characterization of Glutathione Peroxidase and Glutathione S-Transferase Enzymes From Lactobacillus plantarum

“…Moreover, these characters could classy the cytosolic GST C0HLL7 to beta class, which is present only in bacteria. It was also able to conjugate CDNB and was also purified by GSH-affinity chromatography as stated also by Shehu et al (2019). For GPx, Tosatto et al (2008) reported the presence of four important conservation components of GPx active site including; S, Gln, Trp, and Asn.…”

“…Additionally, both Query sequences of GST and GPx belonged to thioredoxin superfamily showing 73.3 and 76.6% identity, respectively. Therefore, sequences shared more than 40% similarity, belonged to the same class (Shehu et al, 2019). Furthermore, multiple sequence alignments with the top two protein sequences appeared in the hit list, revealed 20 conserved residues for GST C0HLL7.…”

“…Furthermore, multiple sequence alignments with the top two protein sequences appeared in the hit list, revealed 20 conserved residues for GST C0HLL7. Shehu et al (2019) reported that two structural motifs conserved in the majority of cytosolic GSTs, both bacterial and eukaryotic origins i.e., N-capping box (S/TXXD) as well as the hydrophobic staple motif, which are essential for the enzymatic folding and stability. The N-capping box, characterized by a reciprocal backbone side-chain hydrogen bond interaction between the N-cap (Ser/Thr) and N3 (Glu/Asp) regions, is involved in the formation and stability of α-helices.…”

“…In the current work, GST showed similar findings where the N-capping box was consisted of Thr27 while the N3 region showed conserved Asp30. Interestingly, glycine residue was part of a buried local sequence: G-X-X-h-T-X-X-D that was conserved in all cytosolic GSTs from mammals to bacteria (Shehu et al, 2019). Moreover, these characters could classy the cytosolic GST C0HLL7 to beta class, which is present only in bacteria.…”