| Autor: |
Olaya-Abril A; Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1ª Planta, Campus de Rabanales, 14071 Córdoba, Spain., Luque-Almagro VM; Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1ª Planta, Campus de Rabanales, 14071 Córdoba, Spain., Hidalgo-Carrillo J; Departamento de Química Orgánica, Instituto Universitario de Investigación en Química Fina y Nanoquímica (IUNAN), Universidad de Córdoba, Edificio Marie Curie, Campus de Rabanales, 14071 Córdoba, Spain., Chicano-Gálvez E; IMIBIC Mass Spectrometry and Molecular Imaging Unit (IMSMI), Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba (UCO), 14004 Córdoba, Spain., Urbano FJ; Departamento de Química Orgánica, Instituto Universitario de Investigación en Química Fina y Nanoquímica (IUNAN), Universidad de Córdoba, Edificio Marie Curie, Campus de Rabanales, 14071 Córdoba, Spain., Moreno-Vivián C; Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1ª Planta, Campus de Rabanales, 14071 Córdoba, Spain., Richardson DJ; School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK., Roldán MD; Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1ª Planta, Campus de Rabanales, 14071 Córdoba, Spain. |
| Abstrakt: |
Denitrification consists of the sequential reduction of nitrate to nitrite, nitric oxide, nitrous oxide, and dinitrogen. Nitrous oxide escapes to the atmosphere, depending on copper availability and other environmental factors. Iron is also a key element because many proteins involved in denitrification contain iron-sulfur or heme centers. The NtrYX two-component regulatory system mediates the responses in a variety of metabolic processes, including denitrification. A quantitative proteomic analysis of a Paracoccus denitrificans NtrY mutant grown under denitrifying conditions revealed the induction of different TonB-dependent siderophore transporters and proteins related to iron homeostasis. This mutant showed lower intracellular iron content than the wild-type strain, and a reduced growth under denitrifying conditions in iron-limited media. Under iron-rich conditions, it releases higher concentrations of siderophores and displayes lower nitrous oxide reductase (NosZ) activity than the wild-type, thus leading to nitrous oxide emission. Bioinformatic and qRT-PCR analyses revealed that NtrYX is a global transcriptional regulatory system that responds to iron starvation and, in turn, controls expression of the iron-responsive regulators fur , rirA , and iscR , the denitrification regulators fnrP and narR , the nitric oxide-responsive regulator nnrS , and a wide set of genes, including the cd 1 -nitrite reductase NirS, nitrate/nitrite transporters and energy electron transport proteins. |
