1a0f

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spinqualitylabelsall models 1a0f, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF GLUTATHIONE S-TRANSFERASE FROM ESCHERICHIA COLI COMPLEXED WITH GLUTATHIONESULFONIC ACID

Overview

Cytosolic glutathione S-transferase is a family of multi-functional, enzymes involved in the detoxification of a large variety of xenobiotic, and endobiotic compounds through glutathione conjugation. The, three-dimensional structure of Escherichia coli glutathione S-transferase, complexed with glutathione sulfonate, N-(N-L-gamma-glutamyl-3-sulfo-L-alanyl)-glycine, has been determined by, the multiple isomorphous replacement method and refined to a, crystallographic R factor of 0.183 at 2.1 A resolution.The E. coli enzyme, is a globular homodimer with dimensions of 58 Ax56 Ax52 A. Each subunit, consisting of a polypeptide of 201 amino acid residues, is divided into a, smaller N-terminal domain (residues 1 to 80) and a larger C-terminal one, (residues 89 to 201). The core of the N-terminal domain is constructed by, a four-stranded beta-sheet and two alpha-helices, and that of the, C-terminal one is constructed by a right-handed bundle of four, alpha-helices. Glutathione sulfonate, a competitive inhibitor against, glutathione, is bound in a cleft between the N and C-terminal domains., Therefore, the E. coli enzyme conserves overall constructions common to, the eukaryotic enzymes, in its polypeptide fold, dimeric assembly, and, glutathione-binding site. In the case of the eukaryotic enzymes, tyrosine, and serine residues near the N terminus are located in the proximity of, the sulfur atom of the bound glutathione, and are proposed to be, catalytically essential. In the E. coli enzyme, Tyr5 and Ser11, corresponding to these residues are not involved in the interaction with, the inhibitor, although they are located in the vicinity of catalytic, site. Instead, Cys10 N and His106 Nepsilon2 atoms are hydrogen-bonded to, the sulfonate group of the inhibitor. On the basis of this structural, study, Cys10 and His106 are ascribed to the catalytic residues that are, distinctive from the family of the eukaryotic enzymes. We propose that, glutathione S-transferases have diverged from a common origin and acquired, different catalytic apparatuses in the process of evolution.

About this Structure

1A0F is a Single protein structure of sequence from Escherichia coli with GTS as ligand. Active as Glutathione transferase, with EC number 2.5.1.18 Full crystallographic information is available from OCA.

Reference

Three-dimensional structure of Escherichia coli glutathione S-transferase complexed with glutathione sulfonate: catalytic roles of Cys10 and His106., Nishida M, Harada S, Noguchi S, Satow Y, Inoue H, Takahashi K, J Mol Biol. 1998 Aug 7;281(1):135-47. PMID:9680481

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