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Title
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Glutathione reductase and thioredoxin reductase at the crossroad: the structure of Schistosoma mansoni thioredoxin glutathione reductase.
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Authors
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F.Angelucci,
A.E.Miele,
G.Boumis,
D.Dimastrogiovanni,
M.Brunori,
A.Bellelli.
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Ref.
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Proteins, 2008,
72,
936-945.
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PubMed id
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Abstract
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Thioredoxin glutathione reductase (TGR) is a key flavoenzyme expressed by
schistosomes that bridges two detoxification pathways crucial for the parasite
survival in the host's organism. In this article we report the crystal structure
(at 2.2 A resolution) of TGR from Schistosoma mansoni (SmTGR), deleted in the
last two residues. The structure reveals the peculiar architecture of this
chimeric enzyme: the small Glutaredoxin (Grx) domain at the N-terminus is joined
to the large thioredoxin reductase (TR) one via an extended complementary
surface, involving residues not conserved in the Grx superfamily; the TR domain
interacts with an identical partner via its C-terminal domain, forming a dimer
with a twisted "W" shape. Although lacking the penultimate Selenocysteine
residue (Sec), the enzyme is still able to reduce oxidized glutathione. These
data update the interpretation of the interdomain communication in TGR enzymes.
The possible function of this enzyme in pathogenic parasites is discussed.
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