|Gene:||npr||Accession Numbers: EG12147 (EcoCyc), b3206, ECK3195|
Synonyms: yhbK, ptsO, rpoR, phosphocarrier protein 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 [Lee13b] 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 [Li08b]. 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 [Lee05f].
Gene Citations: [Jones94c]
|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:
|Biological Process:||GO:0006468 - protein phosphorylation
GO:0010243 - response to organonitrogen compound [Lee13b]
GO:0009401 - phosphoenolpyruvate-dependent sugar phosphotransferase system [UniProtGOA11a]
GO:0016310 - phosphorylation [UniProtGOA11a]
|Molecular Function:||GO:0016772 - transferase activity, transferring phosphorus-containing groups
GO:0004674 - protein serine/threonine kinase activity [UniProtGOA11a]
GO:0016301 - kinase activity [UniProtGOA11a]
GO:0016740 - transferase activity [UniProtGOA11a]
|Cellular Component:||GO:0005737 - cytoplasm
GO:0005829 - cytosol [DiazMejia09]
|MultiFun Terms:||information transfer → protein related → posttranslational modification|
|transport → Accessory Factors Involved in Transport|
|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]|
|Conserved-Region||2 -> 90|
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
Jones94c: 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
Lee05f: 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
Lee13b: 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
Li08b: 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
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
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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