PXD041127

PXD041127 is an original dataset announced via ProteomeXchange.

Title	NirP1 is a small protein that controls nitrite-to-ammonium reduction in cyanobacteria
Description	Unlike all other bacteria, the physiology of cyanobacteria is based on the assimilation of organic matter from inorganic carbon driven by oxygenic photosynthesis. This setting poses special regulatory challenges, particularly in integrating carbon and nitrogen metabolism. Several regulatory factors control the primary nitrogen metabolism, such as the PII protein and proteins interacting with it (PirA, PirC or PipX), or the inactivating factors IF7 and IF17 impacting glutamine synthetase activity. However, regulatory proteins of other enzymes in the nitrogen assimilation pathway have not been described thus far. Here, we show that the 81 amino acids regulatory protein NirP1 in the cyanobacterium Synechocystis sp. PCC 6803 functions as an inhibitor of nitrite reductase, a central enzyme in the assimilation of ammonia from nitrate/nitrite. Ectopic overexpression of the nirP1 gene under standard growth conditions led to a pigmentation phenotype and delayed growth, which was correlated by the excretion of nitrite and dramatic changes in metabolite pools. We show that nitrite excretion occurs in Synechocystis wild type cells upon the shift from high CO2 (HC) to low CO2 (LC) conditions when NirP1 expression becomes activated. The expression of nirP1 is controlled by two transcription factors, NtcA, which binds to a recognition site in a repressive position above the transcription start site (TSS), and an activator, which probably binds to an element 60 to 43 nt upstream of the TSS. Therefore, the joint activity of NtcA and this activator leads to the observed induction of NirP1 under LC conditions, whereas it is repressed by shifts to nitrogen starvation. The data demonstrate that NirP1 plays a crucial role in the coordination of C and N primary metabolism in cyanobacteria by targeting the activity of one of the central enzymes. In natural environments, the excreted nitrite will be utilized by other microorganisms; therefore, NirP1 will ultimately impact the activities and composition of the surrounding microbiome.
HostingRepository	PRIDE
AnnounceDate	2024-02-23
AnnouncementXML	Submission_2024-02-23_06:54:55.674.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Philipp Spaet
SpeciesList	scientific name: Synechocystis sp. PCC 6803; NCBI TaxID: 1148; scientific name: Bacteria; NCBI TaxID: NCBITaxon:2;
ModificationList	No PTMs are included in the dataset
Instrument	Orbitrap Exploris 480

Revision	Datetime	Status	ChangeLog Entry
0	2023-03-27 04:07:55	ID requested
⏵ 1	2024-02-23 06:54:56	announced

10.1101/2023.08.04.552085;

submitter keyword: photosynthesis,cyanobacteria, nitrogen assimilation, Synechocystis sp. PCC 6803, small proteins, gene expression, nitrite reductase, stress acclimation

Prof. Wolfgang R. Hess
contact affiliation	Genetics and Experimental Bioinformatics, Faculty of Biology, Freiburg University, D-79104 Freiburg, Germany
contact email	wolfgang.hess@biologie.uni-freiburg.de
lab head
Philipp Spaet
contact affiliation	University Tuebingen Department of Quantitative Proteomics
contact email	philipp.spaet@uni-tuebingen.de
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD041127
     1. Label: PRIDE project
     2. Name: NirP1 is a small protein that controls nitrite-to-ammonium reduction in cyanobacteria