title: A combined biochemical and computational studies of the rho-class glutathione s-transferase sll1545 of Synechocystis PCC 6803.
abstract: Peroxides are one of the most important radicals that cause oxidative stress. Certain Glutathione S-transferases (GSTs) have been reported to show peroxidase activity. We report a novel peroxidase activity of Synechocystis GST- sll1545. The recombinant protein was purified to homogeneity and characterized. Low Km (0.109μM) and high Vmax (0.663μmolmin-1) values suggest a high preference of sll1545 for cumenehydroperoxide. Disc inhibition assay confirmed the ability of the enzyme to protect cells against peroxide-induced damage. sll1545 has very low sequence and structural similarity with theta and alpha class GSTs that exhibit glutathione-dependent peroxidase activity. Recent data from our laboratory shows that sll1545 is also strongly active against dichloroacetate (DCA), which is a characteristic of zeta class GST. Interestingly, sll1545 shows less than 20% sequence identity with zeta class GST. Molecular dynamic simulation results show that sll1545 was much more structurally different from alpha/theta classes. Our results suggest that sll1545 shows structural variation from zeta, theta/alpha classes of GSTs but have related enzymatic activity. Phylogenetic analysis reveal that sll1545 is evolutionally very distinct from the known GSTs. Overall, the data suggest that Synechocystis sll1545 does not belong to any known GST class and represent a novel GST class, which we have named rho.
authors.affiliation: Molecular & Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong, 793022, Meghalaya, India.
authors.forename: Tripti
authors.initials: T
authors.lastname: Pandey
authors.affiliation: Molecular & Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong, 793022, Meghalaya, India.
authors.forename: Rohit
authors.initials: R
authors.lastname: Shukla
authors.affiliation: Molecular & Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong, 793022, Meghalaya, India.
authors.forename: Harish
authors.initials: H
authors.lastname: Shukla
authors.affiliation: Molecular & Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong, 793022, Meghalaya, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Sonkar
authors.affiliation: Molecular & Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong, 793022, Meghalaya, India. Electronic address: tripathi@gmail.com.
authors.forename: Timir
authors.initials: T
authors.lastname: Tripathi
authors.affiliation: Molecular & Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong, 793022, Meghalaya, India. Electronic address: aksingh_nehu@yahoo.co.
authors.forename: Arvind Kumar
authors.initials: AK
authors.lastname: Singh
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D001555:Benzene Derivatives / Q000737:chemistry; D020134:Catalytic Domain; D017124:Conserved Sequence; D003999:Dichloroacetic Acid / Q000737:chemistry; D005982:Glutathione Transferase / Q000737:chemistry*; D006860:Hydrogen Bonding; D007700:Kinetics; D056004:Molecular Dynamics Simulation; D010084:Oxidation-Reduction; D009195:Peroxidase / Q000737:chemistry*; D010802:Phylogeny; D017433:Protein Structure, Secondary; D040681:Structural Homology, Protein; D013379:Substrate Specificity; D046939:Synechocystis / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D001555:Benzene Derivatives; D003999:Dichloroacetic Acid; D009195:Peroxidase; D005982:Glutathione Transferase; C007164:cumene hydroperoxide
keywords: Glutathione; Glutathione S-transferase; Modeling; Molecular dynamic simulation; Peroxidase; Peroxide; Synechocystis