PDBsum entry 1pl2

Transferase

PDB id: 1pl2

Contents

Protein chain

221 a.a. *

Ligands

ABY ×2

Metals

_CL ×2

Waters ×528

* Residue conservation analysis

PDB id:

1pl2

Name:

Transferase

Title:

Crystal structure of human glutathione transferase (gst) a1-1 t68e mutant in complex with decarboxy-glutathione

Structure:

Glutathione s-transferase a1. Chain: a, b. Synonym: gth1, ha subunit 1, gst-epsilon, gsta1-1, gst class-alpha. Engineered: yes. Mutation: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli. Expression_system_taxid: 562

Biol. unit:

Dimer (from PQS)

Resolution:

1.80Å R-factor: 0.165 R-free: 0.200

Authors:

E.Grahn,E.Jakobsson,A.Gustafsson,L.Grehn,B.Olin,M.Wahlberg,D.Madsen, G.J.Kleywegt,B.Mannervik

Key ref:

E.Grahn et al. (2006). New crystal structures of human glutathione transferase A1-1 shed light on glutathione binding and the conformation of the C-terminal helix. Acta Crystallogr D Biol Crystallogr, 62, 197-207. PubMed id: 16421451 DOI: 10.1107/S0907444905039296

Date:

06-Jun-03 Release date: 22-Jun-04

Protein chains

P08263  (GSTA1_HUMAN) -  Glutathione S-transferase A1 from Homo sapiens

Seq: 222 a.a.

Struc: 221 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class 2: E.C.1.11.1.- - ?????
• Enzyme class 3: E.C.2.5.1.18 - glutathione transferase.
• Reaction: RX + glutathione = an S-substituted glutathione + a halide anion + H⁺
• Enzyme class 4: E.C.5.3.3.- - ?????

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Added reference

DOI no: 10.1107/S0907444905039296

Acta Crystallogr D Biol Crystallogr 62:197-207 (2006)

PubMed id: 16421451

New crystal structures of human glutathione transferase A1-1 shed light on glutathione binding and the conformation of the C-terminal helix.

E.Grahn, M.Novotny, E.Jakobsson, A.Gustafsson, L.Grehn, B.Olin, D.Madsen, M.Wahlberg, B.Mannervik, G.J.Kleywegt.

ABSTRACT

Human glutathione transferase A1-1 is a well studied enzyme, but despite a wealth of structural and biochemical data a number of aspects of its catalytic function are still poorly understood. Here, five new crystal structures of this enzyme are described that provide several insights. Firstly, the structure of a complex of the wild-type human enzyme with glutathione was determined for the first time at 2.0 angstroms resolution. This reveals that glutathione binds in the G site in a very similar fashion as the glutathione portion of substrate analogues in other structures and also that glutathione binding alone is sufficient to stabilize the C-terminal helix of the protein. Secondly, we have studied the complex with a decarboxylated glutathione conjugate that is known to dramatically decrease the activity of the enzyme. The T68E mutant of human glutathione transferase A1-1 recovers some of the activity that is lost with the decarboxylated glutathione, but our structures of this mutant show that none of the earlier explanations of this phenomenon are likely to be correct. Thirdly, and serendipitously, the apo structures also reveal the conformation of the crucial C-terminal region that is disordered in all previous apo structures. The C-terminal region can adopt an ordered helix-like structure even in the apo state, but shows a strong tendency to unwind. Different conformations of the C-terminal regions were observed in the apo states of the two monomers, which suggests that cooperativity could play a role in the activity of the enzyme.

Selected figure(s)

Figure 2.
Figure 2 Crystal structure of human GST A1-1 with only glutathione bound. (a) The homodimer shown in a ribbon representation. The view is along the twofold axis that relates the two subunits. (b) The A subunit with secondary-structure elements labelled. Figs. 2, 3 and 4 were created using Swiss-PDB Viewer 3.7 (Guex & Peitsch, 1997 [Guex, N. & Peitsch, M. C. (1997). Electrophoresis, 18, 2714-2723.]) and POV-Ray 3.6 for Windows (http://www.povray.org/ ).

Figure 5.
Figure 5 Superposition of the C-terminal regions of various GST A1-1 structures. (a) Eight different GST A1-1 structures (16 monomers; PDB codes 1guh , 1gse and 1gsf , as well as the five structures reported here) were superimposed (using the C^ atoms of residues 2-209). Four structures with a glutathione conjugate bound are shown in red, the two apo structures in yellow, the structure with only glutathione bound in blue and the structure with ethacrynic acid bound in green. (b) Superposition of the C-terminal regions of the two apo structures presented here. A monomers are shown in red and B monomers in yellow. Figs. 5 and 6 were created with PyMOL (http://www.pymol.org/ ).

The above figures are reprinted by permission from the IUCr: Acta Crystallogr D Biol Crystallogr (2006, 62, 197-207) copyright 2006.

Figures were selected by an automated process.