Nitrogen control in bacteria.

Merrick, Mike; Edwards, Robert A.

doi:10.1128/mmbr.59.4.604-622.1995

Cited by 425 publications

(270 citation statements)

References 229 publications

(311 reference statements)

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“…According to this hypothesis, in the proteobacterial line of descent the PI, system has acquired a tyrosyl-uridylylating activity, while in the lineage of cyanobacteria, phosphorylation of a seryl residue has occurred. In the sequences of PI, proteins from gram-positive bacteria, the uridylylated tyrosine residue of proteobacterial PI, proteins is replaced by aliphatic amino acids (Merrick and Edwards, 1995) and in the deduced sequence of a PI, protein from Clostridium longisporum (GenBank accession number L49336), the serine residue corresponding to Ser51 of Synechococcus PI, is conserved. Therefore, this protein might b e modified by phosphorylation, as observed in cyanobacteria.…”

Section: Discussionmentioning

confidence: 99%

“…In proteobacteria, Pi, proteins seem to be involved in additional functions to those in E. coli, such as control of N, fixation in Azospirillum brasiliense (de Zamaroczy et al, 1993) or regulation of nitrate reduction in Rhizobium leguminosarum (Amar et a]., 1994). Despite this diversity, in all proteobacteria investigated, PI, is modified by uridylylation (reviewed by Merrick and Edwards, 1995). This suggests conservation of the modification mechanism but diversification of downstream signalling of PI, in different proteobacteria.…”

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confidence: 99%

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Phosphoprotein P_II from Cyanobacteria

Forchhammer¹,

Hedler²

1997

European Journal of Biochemistry

104

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The signal transduction protein PII from Escherichia coli is modified by uridylylation, whereas its counterpart from the cyanobacterium Synechococcus PCC 7942 is phosphorylated at a seryl residue. To elucidate functional conservations between these proteins, we compared the Synechococcus PII protein with the known properties of the E. coli PII protein. Similar to the E. coli protein, Synechococcus PII binds the metabolites 2-oxoglutarate and ATP in a mutually dependent manner. The synergism of ligand binding was analyzed in detail. The ATP-binding site of Synechococcus PII could be labelled with 5'-p-fluorosulfonylbenzoyladenosine. By heterologous expression of the cyanobacterial glnB gene in E. coli we showed that Synechococcus PII can be modified by the E. coli PII uridylyltransferase. The presence of Synechococcus PII prevents signal transduction of E. coli PII to NtrB, presumably by non-functional competition. We therefore propose that the primary function of Synechococcus PII is to sense 2-oxoglutarate, the carbon skeleton required for nitrogen assimilation.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Phosphoprotein P_II from Cyanobacteria

Forchhammer¹,

Hedler²

1997

European Journal of Biochemistry

104

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“…1A). P II proteins have been studied ever since the late 1960s and, subsequently, they have been reviewed extensively [1][2][3][4][5][6][7][8][9][10]. In general, they are encoded by glnB, glnK or nifI genes (in some cases, glnK paralogues are termed glnZ or glnJ) and, in almost all cases, these P II proteins are engaged in coordination of central anabolic metabolism; in particular, the regulation of anabolic reactions related to nitrogen metabolism.…”

Section: General Properties Of P II Proteinsmentioning

confidence: 99%

Sensory properties of the P_II signalling protein family

2015

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P II signalling proteins constitute one of the largest families of signalling proteins in nature. An even larger superfamily of trimeric sensory proteins with the same architectural principle as P II proteins appears in protein structure databases. Large surface-exposed flexible loops protrude from the intersubunit faces, where effector molecules are bound that tune the conformation of the loops. Via this mechanism, P II proteins control target proteins in response to cellular ATP/ADP levels and the 2-oxoglutarate status, thereby coordinating the cellular carbon/nitrogen balance. The antagonistic (ATP versus ADP) and synergistic (2-oxoglutarate and ATP) mode of effector molecule binding is further affected by P II -receptor interaction, leading to a highly sophisticated signalling network organized by P II . Altogether, it appears that P II is a multitasking information processor that, depending on its interaction environment, differentially transmits information on the energy status and the cellular 2-oxoglutarate level. In addition to the basic mode of P II function, several bacterial P II proteins may transmit a signal of the cellular glutamine status via covalent modification. Remarkably, during the evolution of plant chloroplasts, glutamine signalling by P II proteins was re-established by acquisition of a short sequence extension at the C-terminus. This plant-specific C-terminus makes the interaction of plant P II proteins with one of its targets, the arginine biosynthetic enzyme N-acetyl-glutamate kinase, glutamine-dependent. General properties of P II proteinsThe designation 'P II protein' refers to proteins belonging to a class of small trimeric signal-transducing proteins characterized by special structural and functional features (Fig. 1A). P II proteins have been studied ever since the late 1960s and, subsequently, they have been reviewed extensively [1][2][3][4][5][6][7][8][9][10]. In general, they are encoded by glnB, glnK or nifI genes (in some cases, glnK paralogues are termed glnZ or glnJ) and, in almost all cases, these P II proteins are engaged in coordination of central anabolic metabolism; in particular, the regulation of anabolic reactions related to nitrogen metabolism. Members of the P II family occur in almost all free-living bacteria, in nitrogen-fixing archaea and in the chloroplasts of red algae and green plants. As such, they constitute one of the largest signalling protein families in nature. The basic mechanism of signal perception by P II proteins is highly conserved via binding of adenylnucleotides and 2-oxoglutarate (2-OG). P II proteins process the information via conformational changes imposed by effector molecule binding and they transduce the resulting state to their targets via protein interactions. In the course of evolution, P II proteins have been recruited to coordinate a variety of different cellular processes revolving around nitrogen assimilation. In many bacteria, P II proteins of the GlnB subfamily are involved in the regulation of different steps of nitrogen assim...

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“…As a first step towards addressing this imbalance the 3D structure of unmodified Pn has been obtained [5,6]. PII is a highly conserved protein in bacteria and the recent discovery of a second Pii-like protein, GlnK, in E.coli [7] as well as the PH homologues in other bacterial strains have increased the interest in the structure and function studies of the protein [8].…”

Section: Introductionmentioning

confidence: 99%