2X99

Thioredoxin glutathione reductase from Schistosoma mansoni in complex with NADPH

Summary for 2X99

• Entry DOI: 10.2210/pdb2x99/pdb
• Related: 2V6O 2X8C 2X8G 2X8H
• Descriptor: THIOREDOXIN GLUTATHIONE REDUCTASE, FLAVIN-ADENINE DINUCLEOTIDE, NADPH DIHYDRO-NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE, ... (8 entities in total)
• Functional Keywords: flavoprotein, oxidoreductase, thioredoxin, glutathione, nadph, detoxification pathway
• Biological source: SCHISTOSOMA MANSONI
• Total number of polymer chains: 1
• Total formula weight: 68854.69

Authors

Angelucci, F.,Dimastrogiovanni, D.,Boumis, G.,Brunori, M.,Miele, A.E.,Saccoccia, F.,Bellelli, A. (deposition date: 2010-03-15, release date: 2010-07-21, Last modification date: 2017-07-12)

Primary citation

Angelucci, F.,Dimastrogiovanni, D.,Boumis, G.,Brunori, M.,Miele, A.E.,Saccoccia, F.,Bellelli, A.
Mapping the Catalytic Cycle of Schistosoma Mansoni Thioredoxin Glutathione Reductase by X-Ray Crystallography
J.Biol.Chem., 285:32557-, 2010

PubMed Abstract: Schistosomiasis is the second most widespread human parasitic disease. It is principally treated with one drug, praziquantel, that is administered to 100 million people each year; less sensitive strains of schistosomes are emerging. One of the most appealing drug targets against schistosomiasis is thioredoxin glutathione reductase (TGR). This natural chimeric enzyme is a peculiar fusion of a glutaredoxin domain with a thioredoxin selenocysteine (U)-containing reductase domain. Selenocysteine is located on a flexible C-terminal arm that is usually disordered in the available structures of the protein and is essential for the full catalytic activity of TGR. In this study, we dissect the catalytic cycle of Schistosoma mansoni TGR by structural and functional analysis of the U597C mutant. The crystallographic data presented herein include the following: the oxidized form (at 1.9 Å resolution); the NADPH- and GSH-bound forms (2.3 and 1.9 Å, respectively); and a different crystal form of the (partially) reduced enzyme (3.1 Å), showing the physiological dimer and the entire C terminus of one subunit. Whenever possible, we determined the rate constants for the interconversion between the different oxidation states of TGR by kinetic methods. By combining the crystallographic analysis with computer modeling, we were able to throw further light on the mechanism of action of S. mansoni TGR. In particular, we hereby propose the putative functionally relevant conformational change of the C terminus after the transfer of reducing equivalents from NADPH to the redox sites of the enzyme.

PubMed: 20659890
DOI: 10.1074/JBC.M110.141960

Experimental method

X-RAY DIFFRACTION (2.3 Å)