Summary for 2GSR
| Entry DOI | 10.2210/pdb2gsr/pdb |
| Descriptor | CLASS PI GST GLUTATHIONE S-TRANSFERASE, GLUTATHIONE SULFONIC ACID (3 entities in total) |
| Functional Keywords | transferase-transferase inhibitor complex, transferase/transferase inhibitor |
| Biological source | Sus scrofa (pig) |
| Cellular location | Cytoplasm : P80031 |
| Total number of polymer chains | 2 |
| Total formula weight | 47788.65 |
| Authors | Reinemer, P.,Dirr, H.W.,Huber, R. (deposition date: 1996-03-21, release date: 1996-11-08, Last modification date: 2024-02-14) |
| Primary citation | Dirr, H.,Reinemer, P.,Huber, R. Refined crystal structure of porcine class Pi glutathione S-transferase (pGST P1-1) at 2.1 A resolution. J.Mol.Biol., 243:72-92, 1994 Cited by PubMed Abstract: The crystal structure of class Pi glutathione S-transferase from porcine lung (pGST P1-1) in complex with glutathione sulphonate has been refined at 2.11 A resolution, to a crystallographic R-factor of 16.5% for 21, 165 unique reflections. The refined structure includes 3314 protein atoms, 46 inhibitor (glutathione sulphonate) atoms and 254 water molecules. The model shows good stereochemistry, with root-mean-square deviations from ideal bond lengths and bond angles of 0.011 A and 2.8 degrees, respectively. The estimated root-mean-square co-ordinate error is 0.2 A. The protein is a dimer assembled from identical subunits of 207 amino acid residues. The tertiary structure of the pGST P1 subunit is organized as two domains, the N-terminal domain (domain I, residues 1 to 74) and the larger C-terminal domain (domain II, residues 81 to 207). Glutathione sulphonate, a competitive inhibitor, binds to the G-site region (i.e. the glutathione-binding region) of the active site located on each subunit. Each G-site is, however, structurally dependent of the neighbouring subunit as structural elements forming a fully functional G-site are provided by both subunits, with domain I as the major supporting framework. A number of direct and water-mediated polar interactions are involved in sequestering the glutathione analogue at the G-site. The extended conformation assumed by the enzyme-bound inhibitor as well as the strategic interactions between inhibitor and protein, closely resemble those observed for the physiological substrate, reduced glutathione bound at the active site of class Mu glutathione S-transferase 3-3. Hydrogen bonding between the sulphonyl moiety of the inhibitor and the hydroxyl group of an evolutionary conserved tyrosine residue, Tyr7, provides the first direct structural evidence for a catalytic protein group in glutathione S-transferases that is involved in the activation of the substrate glutathione. The catalytic role for Tyr7 has subsequently been confirmed by mutagenesis and kinetic studies. Comparison of the known crystal structures for class Pi, class Mu and class Alpha isoenzymes, indicates that the cytosolic glutathione S-transferases share a common fold and that the structural features for catalysis are similar. PubMed: 7932743DOI: 10.1006/jmbi.1994.1631 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.11 Å) |
Structure validation
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