Database accession: MF2110017
Name: Class pi glutathione S-transferase (Sus scrofa)
PDB ID: 2gsr
Experimental method: X-ray (2.11 Å)
Assembly: homodimer
Source organism: Sus scrofa
Primer publication of the structure:
Dirr H, Reinemer P, Huber R
Refined crystal structure of porcine class Pi glutathione S-transferase (pGST P1-1) at 2.1 A resolution.
(1994) J. Mol. Biol. 243: 72-92
PMID: 7932743
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.
Annotations from the GeneOntology database. Only terms that fit at least two of the interacting proteins are shown. Molecular function:
glutathione transferase activity Catalysis of the reaction: R-X + glutathione = H-X + R-S-glutathione. R may be an aliphatic, aromatic or heterocyclic group; X may be a sulfate, nitrile or halide group.
Biological process:
Cellular component:
Structural annotations of the participating protein chains.Entry contents: 2 distinct polypeptide molecules
Chains: A, B
Notes: No modifications of the original PDB file. Chain identifiers are identical with the PDB's identifiers.
Number of unique protein segments: 1
Name: Glutathione S-transferase P
Source organism: Sus scrofa
Length: 206 residues
Sequence:Sequence according to PDB SEQRESPPYTITYFPVRGRCEAMRMLLADQDQSWKEEVVTMETWPPLKPSCLFRQLPKFQDGDLTLYQSNAILRHLGRSFGLYGKDQKEAALVDMVNDGVEDLRCKYATLIYTNYEAGKEKYVKELPEHLKPFETLLSQNQGGQAFVVGSQISFADYNLLDLLRIHQVLNPSCLDAFPLLSAYVARLSARPKIKAFLASPEHVNRPINGNGK
UniProtKB AC: P80031 (positions: 1-206) Coverage: 99.5%
UniRef90 AC: UniRef90_P80031 (positions: 1-206)
Name: Glutathione S-transferase P
Source organism: Sus scrofa
Length: 206 residues
Sequence:Sequence according to PDB SEQRESPPYTITYFPVRGRCEAMRMLLADQDQSWKEEVVTMETWPPLKPSCLFRQLPKFQDGDLTLYQSNAILRHLGRSFGLYGKDQKEAALVDMVNDGVEDLRCKYATLIYTNYEAGKEKYVKELPEHLKPFETLLSQNQGGQAFVVGSQISFADYNLLDLLRIHQVLNPSCLDAFPLLSAYVARLSARPKIKAFLASPEHVNRPINGNGK
UniProtKB AC: P80031 (positions: 1-206) Coverage: 99.5%
UniRef90 AC: UniRef90_P80031 (positions: 1-206)
Evidence demonstrating that the participating proteins are unstructured prior to the interaction and their folding is coupled to binding. Complex evidence:
Guanidine hydrochloride and urea induced denaturation of the dimer is well described by a two-state model involving significant populations of only the folded dimer and unfolded monomer. Neither a folded, active monomeric form nor stable unfolding intermediates were detected (PMID: 1930226).
Structures from the PDB that contain the same number of proteins, and the proteins from the two structures show a sufficient degree of pairwise similarity, i.e. they belong to the same UniRef90 cluster (the full proteins exhibit at least 90% sequence identity) and convey roughly the same region to their respective interactions (the two regions from the two proteins share a minimum of 70% overlap). No related structure was found in the Protein Data Bank.
