TY - JOUR
T1 - Structural basis for the limited response to oxidative and thiol-conjugating agents by triosephosphate isomerase from the photosynthetic bacteria Synechocystis
AU - Castro-Torres, Eduardo
AU - Jimenez-Sandoval, Pedro
AU - Fernández-de Gortari, Eli
AU - López-Castillo, Margarita
AU - Baruch-Torres, Noe
AU - López-Hidalgo, Marisol
AU - Peralta-Castro, Antolín
AU - Díaz-Quezada, Corina
AU - Sotelo-Mundo, Rogerio R.
AU - Benitez-Cardoza, Claudia G.
AU - Espinoza-Fonseca, L. Michel
AU - Ochoa-Leyva, Adrian
AU - Brieba, Luis G.
N1 - Publisher Copyright:
© 2018 Castro-Torres, Jimenez-Sandoval, Fernández-de Gortari, López-Castillo, Baruch-Torres, López-Hidalgo, Peralta-Castro, Díaz-Quezada, Sotelo-Mundo, Benitez-Cardoza, Espinoza-Fonseca, Ochoa-Leyva and Brieba.
PY - 2018/11/27
Y1 - 2018/11/27
N2 - In plants, the ancestral cyanobacterial triosephosphate isomerase (TPI) was replaced by a duplicated version of the cytosolic TPI. This isoform acquired a transit peptide for chloroplast localization and functions in the Calvin-Benson cycle. To gain insight into the reasons for this gene replacement in plants, we characterized the TPI from the photosynthetic bacteria Synechocystis (SyTPI). SyTPI presents typical TPI enzyme kinetics profiles and assembles as a homodimer composed of two subunits that arrange in a (β-α)8 fold. We found that oxidizing agents diamide (DA) and H2O2, as well as thiol-conjugating agents such as oxidized glutathione (GSSG) and methyl methanethiosulfonate (MMTS), do not inhibit the catalytic activity of SyTPI at concentrations required to inactivate plastidic and cytosolic TPIs from the plant model Arabidopsis thaliana (AtpdTPI and AtcTPI, respectively). The crystal structure of SyTPI revealed that each monomer contains three cysteines, C47, C127, and C176; however only the thiol group of C176 is solvent exposed. While AtcTPI and AtpdTPI are redox-regulated by chemical modifications of their accessible and reactive cysteines, we found that C176 of SyTPI is not sensitive to redox modification in vitro. Our data let us postulate that SyTPI was replaced by a eukaryotic TPI, because the latter contains redox-sensitive cysteines that may be subject to post-translational modifications required for modulating TPI's enzymatic activity.
AB - In plants, the ancestral cyanobacterial triosephosphate isomerase (TPI) was replaced by a duplicated version of the cytosolic TPI. This isoform acquired a transit peptide for chloroplast localization and functions in the Calvin-Benson cycle. To gain insight into the reasons for this gene replacement in plants, we characterized the TPI from the photosynthetic bacteria Synechocystis (SyTPI). SyTPI presents typical TPI enzyme kinetics profiles and assembles as a homodimer composed of two subunits that arrange in a (β-α)8 fold. We found that oxidizing agents diamide (DA) and H2O2, as well as thiol-conjugating agents such as oxidized glutathione (GSSG) and methyl methanethiosulfonate (MMTS), do not inhibit the catalytic activity of SyTPI at concentrations required to inactivate plastidic and cytosolic TPIs from the plant model Arabidopsis thaliana (AtpdTPI and AtcTPI, respectively). The crystal structure of SyTPI revealed that each monomer contains three cysteines, C47, C127, and C176; however only the thiol group of C176 is solvent exposed. While AtcTPI and AtpdTPI are redox-regulated by chemical modifications of their accessible and reactive cysteines, we found that C176 of SyTPI is not sensitive to redox modification in vitro. Our data let us postulate that SyTPI was replaced by a eukaryotic TPI, because the latter contains redox-sensitive cysteines that may be subject to post-translational modifications required for modulating TPI's enzymatic activity.
KW - Oxidative damage
KW - Protein evolution
KW - Thiol-based redox regulation
KW - Triosephosphate isomerase
KW - X-ray structure
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U2 - 10.3389/fmolb.2018.00103
DO - 10.3389/fmolb.2018.00103
M3 - Article
AN - SCOPUS:85059231316
SN - 2296-889X
VL - 5
JO - Frontiers in Molecular Biosciences
JF - Frontiers in Molecular Biosciences
IS - NOV
M1 - 103
ER -