title: NTRC new ways of using NADPH in the chloroplast.
abstract: Despite being the primary source of energy in the biosphere, photosynthesis is a process that inevitably produces reactive oxygen species. Chloroplasts are a major source of hydrogen peroxide production in plant cells; therefore, different systems for peroxide reduction, such as ascorbate peroxidase and peroxiredoxins (Prxs), are found in this organelle. Most of the reducing power required for hydrogen peroxide reduction by these systems is provided by Fd reduced by the photosynthetic electron transport chain; hence, the function of these systems is highly dependent on light. Recently, it was described a novel plastidial enzyme, stated NTRC, formed by a thioredoxin reductase (NTR) domain at the N-terminus and a thioredoxin (Trx) domain at the C-terminus. NTRC is able to conjugate both NTR and Trx activities to efficiently reduce 2-Cys Prx using NADPH as a source of reducing power. Based on these results, it was proposed that NTRC is a new pathway to transfer reducing power to the chloroplast detoxification system, allowing the use of NADPH, besides reduced Fd, for such function. In this article, the most important features of NTRC are summarized and the implications of this novel activity in the context of chloroplast protection against oxidative damage are discussed.
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla y CSIC, Avda Américo Vespucio 49, 41092 Sevilla, Spain.
authors.forename: María C
authors.initials: MC
authors.lastname: Spínola
authors.forename: Juan M
authors.initials: JM
authors.lastname: Pérez-Ruiz
authors.forename: Pablo
authors.initials: P
authors.lastname: Pulido
authors.forename: Kerstin
authors.initials: K
authors.lastname: Kirchsteiger
authors.forename: Manuel
authors.initials: M
authors.lastname: Guinea
authors.forename: Maricruz
authors.initials: M
authors.lastname: González
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Cejudo
mesh_terms: D001665:Binding Sites / Q000235:genetics; D002736:Chloroplasts / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008954:Models, Biological; D009249:NADP / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D010944:Plants / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D013879:Thioredoxins / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D013879:Thioredoxins; D009249:NADP; D006861:Hydrogen Peroxide