Escherichia coli K-12 substr. MG1655 Polypeptide: phosphorelay protein Npr

Gene: npr Accession Numbers: EG12147 (EcoCyc), b3206, ECK3195

Synonyms: yhbK, ptsO, rpoR, phosphocarrier protein NPr

Regulation Summary Diagram: ?

Regulation summary diagram for npr

Alternative forms of phosphorelay protein Npr: Npr phosphorylated

NPr is the second phosphotransfer protein of the nitrogen phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTSNtr) in E. coli K-12. The exact function of the PTSNtr is not clear - it has been implicated in the regulation of nitrogen metabolism [Lee13] and in potassium homeostasis (reviewed in [PflugerGrau10] but see also [Ninfa11]).

PtsP, also known as enzyme INtr, phosphorylates NPr in vitro. This reaction occurs at an optimum pH of 8.0, is dependent on Mg2+, is stimulated by high ionic strength, and has two Km values for Npr of 2 and 10 μM [Rabus99]. Purified Npr is active as a phosphoryl acceptor from EINtr and is capable of phosphotransfer to PtsN (also known as EIIANtr); a solution structure of Npr has been obtained [Li08c]. PtsP and NPr contribute to the phosphorylation of PtsN in vivo, but in the absence of these two phosphotransfer proteins PtsI and HPr of the canonical PTSsugar can substitute. The absence of all four of these phosphotransfer proteins results in extremely limited phosphorylation of EIIANtr [Zimmer08].

Efficient transfer of phosphate to Npr, from a number of enzyme IIAs of the PTSsugar system and from EIIANtr can be observed in vitro [Powell95].

npr forms part of the sigma54 operon in E. coli K-12 [Powell95].

npr mutants have been show through phenotype microarray analysis to be more resistant than wild-type to leucine-containing peptides [Lee05a].

Gene Citations: [Jones94a]

Locations: cytosol

Map Position: [3,345,988 -> 3,346,260] (72.12 centisomes, 260°)
Length: 273 bp / 90 aa

Molecular Weight of Polypeptide: 9.81 kD (from nucleotide sequence)

Unification Links: ASAP:ABE-0010524 , EchoBASE:EB2067 , EcoGene:EG12147 , EcoliWiki:b3206 , ModBase:P0A9N0 , OU-Microarray:b3206 , PortEco:npr , PR:PRO_000023635 , Protein Model Portal:P0A9N0 , RefSeq:NP_417673 , RegulonDB:EG12147 , SMR:P0A9N0 , String:511145.b3206 , UniProt:P0A9N0

Relationship Links: InterPro:IN-FAMILY:IPR000032 , InterPro:IN-FAMILY:IPR001020 , InterPro:IN-FAMILY:IPR002114 , Pfam:IN-FAMILY:PF00381 , Prints:IN-FAMILY:PR00107 , Prosite:IN-FAMILY:PS00369 , Prosite:IN-FAMILY:PS00589 , Prosite:IN-FAMILY:PS51350

In Reactions of unknown directionality:

Not in pathways:
Npr phosphorylated + PtsN = PtsN-phosphorylated + Npr
PtsP-phosphorylated + Npr = Npr phosphorylated + PtsP

GO Terms:

Biological Process: GO:0006468 - protein phosphorylation Inferred from experiment [Rabus99, Powell95]
GO:0010243 - response to organonitrogen compound Inferred from experiment [Lee13]
GO:0009401 - phosphoenolpyruvate-dependent sugar phosphotransferase system Inferred by computational analysis [UniProtGOA11]
GO:0016310 - phosphorylation Inferred by computational analysis [UniProtGOA11]
Molecular Function: GO:0016772 - transferase activity, transferring phosphorus-containing groups Inferred from experiment [Rabus99, Powell95]
GO:0004674 - protein serine/threonine kinase activity Inferred by computational analysis [UniProtGOA11]
GO:0016301 - kinase activity Inferred by computational analysis [UniProtGOA11]
GO:0016740 - transferase activity Inferred by computational analysis [UniProtGOA11]
Cellular Component: GO:0005737 - cytoplasm Inferred by computational analysis [UniProtGOA11a, UniProtGOA11]
GO:0005829 - cytosol Inferred by computational analysis [DiazMejia09]

MultiFun Terms: information transfer protein related posttranslational modification
transport Accessory Factors Involved in Transport

Essentiality data for npr knockouts: ?

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB enriched Yes 37 Aerobic 6.95   Yes [Gerdes03, Comment 1]
LB Lennox Yes 37 Aerobic 7   Yes [Baba06, Comment 2]
M9 medium with 1% glycerol Yes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 3]
MOPS medium with 0.4% glucose Yes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 2]

Last-Curated ? 22-Apr-2013 by Mackie A , Macquarie University

Sequence Features

Protein sequence of phosphorelay protein Npr with features indicated

Feature Class Location Citations Comment
Conserved-Region 2 -> 90
UniProt: HPr;
Active-Site 16
UniProt: Pros-phosphohistidine intermediate; Non-Experimental Qualifier: by similarity.
Phosphorylation-Modification 16
UniProt: Pros-phosphohistidine intermediate; Non-Experimental Qualifier: by similarity;

Gene Local Context (not to scale): ?

Gene local context diagram

Transcription Units:

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram

Transcription-unit diagram


10/20/97 Gene b3206 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG12147; confirmed by SwissProt match.


Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554

DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114

Gerdes03: Gerdes SY, Scholle MD, Campbell JW, Balazsi G, Ravasz E, Daugherty MD, Somera AL, Kyrpides NC, Anderson I, Gelfand MS, Bhattacharya A, Kapatral V, D'Souza M, Baev MV, Grechkin Y, Mseeh F, Fonstein MY, Overbeek R, Barabasi AL, Oltvai ZN, Osterman AL (2003). "Experimental determination and system level analysis of essential genes in Escherichia coli MG1655." J Bacteriol 185(19);5673-84. PMID: 13129938

Jones94a: Jones DH, Franklin FC, Thomas CM (1994). "Molecular analysis of the operon which encodes the RNA polymerase sigma factor sigma 54 of Escherichia coli." Microbiology 1994;140 ( Pt 5);1035-43. PMID: 8025669

Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394

Lee05a: Lee CR, Koo BM, Cho SH, Kim YJ, Yoon MJ, Peterkofsky A, Seok YJ (2005). "Requirement of the dephospho-form of enzyme IIANtr for derepression of Escherichia coli K-12 ilvBN expression." Mol Microbiol 58(1);334-44. PMID: 16164569

Lee13: Lee CR, Park YH, Kim M, Kim YR, Park S, Peterkofsky A, Seok YJ (2013). "Reciprocal regulation of the autophosphorylation of enzyme INtr by glutamine and α-ketoglutarate in Escherichia coli." Mol Microbiol 88(3);473-85. PMID: 23517463

Li08c: Li X, Peterkofsky A, Wang G (2008). "Solution structure of NPr, a bacterial signal-transducing protein that controls the phosphorylation state of the potassium transporter-regulating protein IIA Ntr." Amino Acids 35(3);531-9. PMID: 18421563

Ninfa11: Ninfa AJ (2011). "Unnecessary signaling: poorly named?." J Bacteriol 193(18);4571-3. PMID: 21742895

PflugerGrau10: Pfluger-Grau K, Gorke B (2010). "Regulatory roles of the bacterial nitrogen-related phosphotransferase system." Trends Microbiol 18(5);205-14. PMID: 20202847

Powell95: Powell BS, Court DL, Inada T, Nakamura Y, Michotey V, Cui X, Reizer A, Saier MH, Reizer J (1995). "Novel proteins of the phosphotransferase system encoded within the rpoN operon of Escherichia coli. Enzyme IIANtr affects growth on organic nitrogen and the conditional lethality of an erats mutant." J Biol Chem 1995;270(9);4822-39. PMID: 7876255

Rabus99: Rabus R, Reizer J, Paulsen I, Saier MH (1999). "Enzyme I(Ntr) from Escherichia coli. A novel enzyme of the phosphoenolpyruvate-dependent phosphotransferase system exhibiting strict specificity for its phosphoryl acceptor, NPr." J Biol Chem 274(37);26185-91. PMID: 10473571

UniProt09: UniProt Consortium (2009). "UniProt version 15.8 released on 2009-10-01 00:00:00." Database.

UniProt10: UniProt Consortium (2010). "UniProt version 2010-07 released on 2010-06-15 00:00:00." Database.

UniProt13: UniProt Consortium (2013). "UniProt version 2013-08 released on 2013-08-01 00:00:00." Database.

UniProtGOA11: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

UniProtGOA11a: UniProt-GOA (2011). "Gene Ontology annotation based on the manual assignment of UniProtKB Subcellular Location terms in UniProtKB/Swiss-Prot entries."

Zimmer08: Zimmer B, Hillmann A, Gorke B (2008). "Requirements for the phosphorylation of the Escherichia coli EIIANtr protein in vivo." FEMS Microbiol Lett 286(1);96-102. PMID: 18625021

Other References Related to Gene Regulation

Kumar11: Kumar R, Shimizu K (2011). "Transcriptional regulation of main metabolic pathways of cyoA, cydB, fnr, and fur gene knockout Escherichia coli in C-limited and N-limited aerobic continuous cultures." Microb Cell Fact 10;3. PMID: 21272324

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Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
Page generated by SRI International Pathway Tools version 19.0 on Tue Oct 6, 2015, biocyc13.