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The contribution of NADPH thioredoxin reductase C (NTRC) and sulfiredoxin to 2-Cys peroxiredoxin overoxidation in Arabidopsis thaliana chloroplasts

Authors :
Manuel Guinea
Leonor Puerto-Galán
Francisco Javier Cejudo
Juan Manuel Pérez-Ruiz
Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular
Source :
idUS. Depósito de Investigación de la Universidad de Sevilla, instname, Digital.CSIC. Repositorio Institucional del CSIC, Journal of Experimental Botany
Publication Year :
2015
Publisher :
Oxford University Press (OUP), 2015.

Abstract

Highlight This work shows the dominant effect of NADPH thioredoxin reductase C (NTRC) over sulfiredoxin on 2-Cys peroxiredoxin (2-Cys Prx) overoxidation, and uncovers an NTRC-independent, light-dependent component contributing to 2-Cys Prx overoxidation in Arabidopsis thaliana chloroplasts.<br />Hydrogen peroxide is a harmful by-product of photosynthesis, which also has important signalling activity. Therefore, the level of hydrogen peroxide needs to be tightly controlled. Chloroplasts harbour different antioxidant systems including enzymes such as the 2-Cys peroxiredoxins (2-Cys Prxs). Under oxidizing conditions, 2-Cys Prxs are susceptible to inactivation by overoxidation of their peroxidatic cysteine, which is enzymatically reverted by sulfiredoxin (Srx). In chloroplasts, the redox status of 2-Cys Prxs is highly dependent on NADPH-thioredoxin reductase C (NTRC) and Srx; however, the relationship of these activities in determining the level of 2-Cys Prx overoxidation is unknown. Here we have addressed this question by a combination of genetic and biochemical approaches. An Arabidopsis thaliana double knockout mutant lacking NTRC and Srx shows a phenotype similar to the ntrc mutant, while the srx mutant resembles wild-type plants. The deficiency of NTRC causes reduced overoxidation of 2-Cys Prxs, whereas the deficiency of Srx has the opposite effect. Moreover, in vitro analyses show that the disulfide bond linking the resolving and peroxidatic cysteines protects the latter from overoxidation, thus explaining the dominant role of NTRC on the level of 2-Cys Prx overoxidation in vivo. The overoxidation of chloroplast 2-Cys Prxs shows no circadian oscillation, in agreement with the fact that neither the NTRC nor the SRX genes show circadian regulation of expression. Additionally, the low level of 2-Cys Prx overoxidation in the ntrc mutant is light dependent, suggesting that the redox status of 2-Cys Prxs in chloroplasts depends on light rather than the circadian clock.

Details

ISSN :
14602431 and 00220957
Volume :
66
Database :
OpenAIRE
Journal :
Journal of Experimental Botany
Accession number :
edsair.doi.dedup.....2776d963573155589d22ceee165aff41
Full Text :
https://doi.org/10.1093/jxb/eru512