3SBC

Crystal structure of Saccharomyces cerevisiae TSA1C47S mutant protein

Summary for 3SBC

• Entry DOI: 10.2210/pdb3sbc/pdb
• Descriptor: Peroxiredoxin TSA1, (2R,3S)-1,4-DIMERCAPTOBUTANE-2,3-DIOL, (2S,3S)-1,4-DIMERCAPTOBUTANE-2,3-DIOL, ... (4 entities in total)
• Functional Keywords: alpha-beta fold, peroxidase, cytosol, oxidoreductase
• Biological source: Saccharomyces cerevisiae (Baker's yeast)
• Cellular location: Cytoplasm: P34760
• Total number of polymer chains: 10
• Total formula weight: 238594.96

Authors

Tairum Jr., C.A.,Horta, B.B.,Netto, L.E.S.,Oliveira, M.A. (deposition date: 2011-06-03, release date: 2012-08-08, Last modification date: 2024-02-28)

Primary citation

Tairum, C.A.,de Oliveira, M.A.,Horta, B.B.,Zara, F.J.,Netto, L.E.
Disulfide biochemistry in 2-cys peroxiredoxin: requirement of Glu50 and Arg146 for the reduction of yeast Tsa1 by thioredoxin.
J.Mol.Biol., 424:28-41, 2012

PubMed Abstract: 2-Cys peroxiredoxin (Prx) enzymes are ubiquitously distributed peroxidases that make use of a peroxidatic cysteine (Cys(P)) to decompose hydroperoxides. A disulfide bond is generated as a consequence of the partial unfolding of the α-helix that contains Cys(P). Therefore, during its catalytic cycle, 2-Cys Prx alternates between two states, locally unfolded and fully folded. Tsa1 (thiol-specific antioxidant protein 1 from yeast) is by far the most abundant Cys-based peroxidase in Saccharomyces cerevisiae. In this work, we present the crystallographic structure at 2.8Å resolution of Tsa1(C47S) in the decameric form [(α(2))(5)] with a DTT molecule bound to the active site, representing one of the few available reports of a 2-Cys Prx (AhpC-Prx1 subfamily) (AhpC, alkyl hydroperoxide reductase subunit C) structure that incorporates a ligand. The analysis of the Tsa1(C47S) structure indicated that Glu50 and Arg146 participate in the stabilization of the Cys(P) α-helix. As a consequence, we raised the hypothesis that Glu50 and Arg146 might be relevant to the Cys(P) reactivity. Therefore, Tsa1(E50A) and Tsa1(R146Q) mutants were generated and were still able to decompose hydrogen peroxide, presenting a second-order rate constant in the range of 10(6)M(-1)s(-1). Remarkably, although Tsa1(E50A) and Tsa1(R146Q) were efficiently reduced by the low-molecular-weight reductant DTT, these mutants displayed only marginal thioredoxin (Trx)-dependent peroxidase activity, indicating that Glu50 and Arg146 are important for the Tsa1-Trx interaction. These results may impact the comprehension of downstream events of signaling pathways that are triggered by the oxidation of critical Cys residues, such as Trx.

PubMed: 22985967
DOI: 10.1016/j.jmb.2012.09.008

Experimental method

X-RAY DIFFRACTION (2.8 Å)