1PKZ

Crystal structure of human glutathione transferase (GST) A1-1

Summary for 1PKZ

• Entry DOI: 10.2210/pdb1pkz/pdb
• Related: 1PKW 1PL1 1PL2
• Descriptor: Glutathione S-transferase A1, 2-HYDROXYETHYL DISULFIDE (3 entities in total)
• Functional Keywords: domain1:alpha beta, domain2:alpha-helical, transferase
• Biological source: Homo sapiens (human)
• Cellular location: Cytoplasm: P08263
• Total number of polymer chains: 2
• Total formula weight: 51680.74

Authors

Grahn, E.,Jakobsson, E.,Gustafsson, A.,Grehn, L.,Olin, B.,Wahlberg, M.,Madsen, D.,Kleywegt, G.J.,Mannervik, B. (deposition date: 2003-06-06, release date: 2004-06-22, Last modification date: 2024-11-20)

Primary citation

Grahn, E.,Novotny, M.,Jakobsson, E.,Gustafsson, A.,Grehn, L.,Olin, B.,Madsen, D.,Wahlberg, M.,Mannervik, B.,Kleywegt, G.J.
New crystal structures of human glutathione transferase A1-1 shed light on glutathione binding and the conformation of the C-terminal helix.
Acta Crystallogr.,Sect.D, 62:197-207, 2006

PubMed 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.

PubMed: 16421451
DOI: 10.1107/S0907444905039296

Experimental method

X-RAY DIFFRACTION (2.1 Å)