Structural Basis for the Limited Response to Oxidative and Thiol-Conjugating Agents by Triosephosphate Isomerase From the Photosynthetic Bacteria Synechocystis
Por:
Castro-Torres, Eduardo, Jimenez-Sandoval, Pedro, Fernandez-de Gortari, Eli, Lopez-Castillo, Margarita, Baruch-Torres, Noe, Lopez-Hidalgo, Marisol, Peralta-Castro, Antolin, Diaz-Quezada, Corina, Sotelo-Mundo, Rogerio R., Benitez-Cardoza, Claudia G., Espinoza-Fonseca, L. Michel, Ochoa-Leyva, Adrian, Brieba, Luis G.
Publicada:
27 nov 2018
Resumen:
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 (beta-alpha)(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 AtpdTPl are redoxregulated 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.
Filiaciones:
Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Guanajuato, Mexico
Division of Cardiovascular Medicine, Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI, United States
Laboratorio de Investigación Bioquímica, Programa Institucional en Biomedicina Molecular ENMyH-IPN, Ciudad de México, Mexico
Laboratorio de Estructura Biomolecular, Centro de Investigación en Alimentación y Desarrollo, A.C., Hermosillo, Mexico
Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
Ctr Invest & Estudios Avanzados IPN, Lab Nacl Genom Biodiversidad, Guanajuato, Mexico
Univ Michigan, Dept Internal Med, Div Cardiovasc Med, Ctr Arrhythmia Res, Ann Arbor, MI 48109 USA
Programa Inst Biomed Mol ENMyH IPN, Lab Invest Bioquim, Ciudad De Mexico, Mexico
Ctr Invest Alimentac & Desarrolb AC, Lab Estruct Bimol, Hermosillo, Sonora, Mexico
Univ Nacl Autonoma Mexico, Dept Microbiol Mol, Inst Biotecnol, Cuernavaca, Morelos, Mexico
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