User:Johanna Spaniol/Sandbox 1

From Proteopedia

Glutathione S-Transferase form a wide family of enzymes divided in mammals into 5 classes (alpha, mu, pi, sigma and theta). These enzymes are involved in the cellular detoxification : they reduce the reactivity of toxic compounds by catalysing the conjugation of glutathione (GSH) with a wide range of endogenous and xenobiotic alkylating agents (http://en.wikipedia.org/wiki/Xenobiotic). Gluthathione theta class S-Transferase is an enzyme member of the GTS family, located in hepatic cells of procaryotes and eucaryotes in the cytosol and in mitochondrias. This enzyme is a dimeric protein of 45-55kDa. The two subunits are encountered: the C-terminal domain of the first subunit is in contact with the N-terminal domain of the 2nd subunit. So each subunit has an and a . The two subunits form the dimeric protein and there are some specific residues forming the dimer interface ( and ).

The protein has a (80residues), a comprising two helices connected by a long loop and a specific . The extension completely buries the and occludes most of the . In these sites occurs the following reaction: RX + glutathione = HX + R-S-glutathione.

A narrow tunnel leading from the active site to the surface may provide a pathway for the entry of substrates and the release of products.

About the structure

2LJR is a 2 chains structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.

Reference

Rossjohn J, McKinstry WJ, Oakley AJ, Verger D, Flanagan J, Chelvanayagam G, Tan KL, Board PG, Parker MW. Human theta class glutathione transferase: the crystal structure reveals a sulfate-binding pocket within a buried active site. Structure. 1998 Mar 15;6(3):309-22. PMID:9551553

http://www.ncbi.nlm.nih.gov/ http://www.rcsb.org/pdb/home/home.do http://srs.ebi.ac.uk/