PDBsum entry 2x8h

Oxidoreductase

PDB id: 2x8h

Contents

Protein chain

588 a.a. *

Ligands

FAD

GSH

BME

PGE ×2

PG4

PEG ×4

Metals

_CA

Waters ×365

* Residue conservation analysis

PDB id:

2x8h

Name:

Oxidoreductase

Title:

Thioredoxin glutathione reductase from schistosoma mansoni in complex with gsh

Structure:

Thioredoxin glutathione reductase. Chain: a. Engineered: yes

Source:

Schistosoma mansoni. Blood fluke. Organism_taxid: 6183. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

1.90Å R-factor: 0.181 R-free: 0.194

Authors:

F.Angelucci,D.Dimastrogiovanni,G.Boumis,M.Brunori,A.E.Miele, F.Saccoccia,A.Bellelli

Key ref:

F.Angelucci et al. (2010). Mapping the catalytic cycle of Schistosoma mansoni thioredoxin glutathione reductase by X-ray crystallography. J Biol Chem, 285, 32557-32567. PubMed id: 20659890 DOI: 10.1074/jbc.M110.141960

Date:

09-Mar-10 Release date: 21-Jul-10

Protein chain

Q962Y6  (Q962Y6_SCHMA) -  Thioredoxin glutathione reductase from Schistosoma mansoni

Seq: 598 a.a.

Struc: 588 a.a.

Enzyme reactions

• Enzyme class: E.C.1.6.4.5 - Transferred entry: 1.8.1.9.

DOI no: 10.1074/jbc.M110.141960

J Biol Chem 285:32557-32567 (2010)

PubMed id: 20659890

Mapping the catalytic cycle of Schistosoma mansoni thioredoxin glutathione reductase by X-ray crystallography.

F.Angelucci, D.Dimastrogiovanni, G.Boumis, M.Brunori, A.E.Miele, F.Saccoccia, A.Bellelli.

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.