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Li B, Wang XQ, Li QY, Xu D, Li J, Hou WT, Chen Y, Jiang YL, Zhou CZ. Allosteric regulation of nitrate transporter NRT via the signaling protein PII. Proc Natl Acad Sci U S A 2024; 121:e2318320121. [PMID: 38457518 PMCID: PMC10945777 DOI: 10.1073/pnas.2318320121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Accepted: 01/10/2024] [Indexed: 03/10/2024] Open
Abstract
Coordinated carbon and nitrogen metabolism is crucial for bacteria living in the fluctuating environments. Intracellular carbon and nitrogen homeostasis is maintained by a sophisticated network, in which the widespread signaling protein PII acts as a major regulatory hub. In cyanobacteria, PII was proposed to regulate the nitrate uptake by an ABC (ATP-binding cassette)-type nitrate transporter NrtABCD, in which the nucleotide-binding domain of NrtC is fused with a C-terminal regulatory domain (CRD). Here, we solved three cryoelectron microscopy structures of NrtBCD, bound to nitrate, ATP, and PII, respectively. Structural and biochemical analyses enable us to identify the key residues that form a hydrophobic and a hydrophilic cavity along the substrate translocation channel. The core structure of PII, but not the canonical T-loop, binds to NrtC and stabilizes the CRD, making it visible in the complex structure, narrows the substrate translocation channel in NrtB, and ultimately locks NrtBCD at an inhibited inward-facing conformation. Based on these results and previous reports, we propose a putative transport cycle driven by NrtABCD, which is allosterically inhibited by PII in response to the cellular level of 2-oxoglutarate. Our findings provide a distinct regulatory mechanism of ABC transporter via asymmetrically binding to a signaling protein.
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Affiliation(s)
- Bo Li
- Division of Life Sciences and Medicine, School of Life Sciences, University of Science and Technology of China, Hefei230027, China
| | - Xiao-Qian Wang
- Division of Life Sciences and Medicine, School of Life Sciences, University of Science and Technology of China, Hefei230027, China
| | - Qin-Yao Li
- Division of Life Sciences and Medicine, School of Life Sciences, University of Science and Technology of China, Hefei230027, China
| | - Da Xu
- Division of Life Sciences and Medicine, School of Life Sciences, University of Science and Technology of China, Hefei230027, China
| | - Jing Li
- Division of Life Sciences and Medicine, School of Life Sciences, University of Science and Technology of China, Hefei230027, China
| | - Wen-Tao Hou
- Division of Life Sciences and Medicine, School of Life Sciences, University of Science and Technology of China, Hefei230027, China
| | - Yuxing Chen
- Division of Life Sciences and Medicine, School of Life Sciences, University of Science and Technology of China, Hefei230027, China
| | - Yong-Liang Jiang
- Division of Life Sciences and Medicine, School of Life Sciences, University of Science and Technology of China, Hefei230027, China
| | - Cong-Zhao Zhou
- Division of Life Sciences and Medicine, School of Life Sciences, University of Science and Technology of China, Hefei230027, China
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Iskhakova ZI, Zhuravleva DE, Heim C, Hartmann MD, Laykov AV, Forchhammer K, Kayumov AR. PotN represents a novel energy‐state sensing PII subfamily, occurring in firmicutes. FEBS J 2022; 289:5305-5321. [DOI: 10.1111/febs.16431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 02/19/2022] [Accepted: 03/10/2022] [Indexed: 01/19/2023]
Affiliation(s)
| | | | - Christopher Heim
- Department of Protein Evolution Max Planck Institute for Developmental Biology Tübingen Germany
| | - Marcus D. Hartmann
- Department of Protein Evolution Max Planck Institute for Developmental Biology Tübingen Germany
| | | | - Karl Forchhammer
- Institut für Mikrobiologie Eberhard‐Karls‐Universität Tübingen Germany
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Grau FC, Burkovski A, Muller YA. Crystal structures of adenylylated and unadenylylated P II protein GlnK from Corynebacterium glutamicum. Acta Crystallogr D Struct Biol 2021; 77:325-335. [PMID: 33645536 PMCID: PMC7919409 DOI: 10.1107/s2059798321000735] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 01/21/2021] [Indexed: 11/10/2022] Open
Abstract
PII proteins are ubiquitous signaling proteins that are involved in the regulation of the nitrogen/carbon balance in bacteria, archaea, and some plants and algae. Signal transduction via PII proteins is modulated by effector molecules and post-translational modifications in the PII T-loop. Whereas the binding of ADP, ATP and the concomitant binding of ATP and 2-oxoglutarate (2OG) engender two distinct conformations of the T-loop that either favor or disfavor the interaction with partner proteins, the structural consequences of post-translational modifications such as phosphorylation, uridylylation and adenylylation are far less well understood. In the present study, crystal structures of the PII protein GlnK from Corynebacterium glutamicum have been determined, namely of adenylylated GlnK (adGlnK) and unmodified unadenylylated GlnK (unGlnK). AdGlnK has been proposed to act as an inducer of the transcription repressor AmtR, and the adenylylation of Tyr51 in GlnK has been proposed to be a prerequisite for this function. The structures of unGlnK and adGlnK allow the first atomic insights into the structural implications of the covalent attachment of an AMP moiety to the T-loop. The overall GlnK fold remains unaltered upon adenylylation, and T-loop adenylylation does not appear to interfere with the formation of the two major functionally important T-loop conformations, namely the extended T-loop in the canonical ADP-bound state and the compacted T-loop that is adopted upon the simultaneous binding of Mg-ATP and 2OG. Thus, the PII-typical conformational switching mechanism appears to be preserved in GlnK from C. glutamicum, while at the same time the functional repertoire becomes expanded through the accommodation of a peculiar post-translational modification.
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Affiliation(s)
- Florian C. Grau
- Division of Biotechnology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestrasse 91, 91052 Erlangen, Germany
| | - Andreas Burkovski
- Division of Microbiology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, 91058 Erlangen, Germany
| | - Yves A. Muller
- Division of Biotechnology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Henkestrasse 91, 91052 Erlangen, Germany
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Complete Genome Sequence of Lactobacillus hilgardii LMG 7934, Carrying the Gene Encoding for the Novel PII-Like Protein PotN. Curr Microbiol 2020; 77:3538-3545. [PMID: 32803419 DOI: 10.1007/s00284-020-02161-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/07/2020] [Indexed: 02/02/2023]
Abstract
Lactic acid bacteria are widespread in various ecological niches with the excess of nutrients and have reduced capabilities to adapt to starvation. Among more than 280 Lactobacillus species known to the date, only five, including Lactobacillus hilgardii, carry in their genome the gene encoding for PII-like protein, one of the central regulators of cellular metabolism generally responding to energy- and carbon-nitrogen status in many free-living Bacteria, Archaea and in plant chloroplasts. In contrast to the classical PII encoding genes, in L. hilgardii genome the gene for PII homologue is located within the potABCD operon, encoding the ABC transporter for polyamines. Based on the unique genetic context and low sequence identity with genes of any other so-far characterized PII subfamilies, we termed this gene potN (Pot-protein, Nucleotide-binding). The second specific feature of L. hilgardii genome is that many genes encoding the proteins with similar function are present in two copies, while with low mutual identity. Thus, L. hilgardii LMG 7934 genome carries two genes of glutamine synthetase with 55% identity. One gene is located within classical glnRA operon with the gene of GlnR-like transcriptional regulator, while the second is monocistronic. Together with the relative large genome of L. hilgardii as compared to other Lactobacilli (2.771.862 bp vs ~ 2.2 Mbp in median), these data suggest significant re-arrangements of the genome and a wider range of adaptive capabilities of L. hilgardii in comparison to other bacteria of the genus Lactobacillus.
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Selim KA, Haffner M, Watzer B, Forchhammer K. Tuning the in vitro sensing and signaling properties of cyanobacterial PII protein by mutation of key residues. Sci Rep 2019; 9:18985. [PMID: 31831819 PMCID: PMC6908673 DOI: 10.1038/s41598-019-55495-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/13/2019] [Indexed: 11/09/2022] Open
Abstract
PII proteins comprise an ancient superfamily of signal transduction proteins, widely distributed among all domains of life. In general, PII proteins measure and integrate the current carbon/nitrogen/energy status of the cell through interdependent binding of ATP, ADP and 2-oxogluterate. In response to effector molecule binding, PII proteins interact with various PII-receptors to tune central carbon- and nitrogen metabolism. In cyanobacteria, PII regulates, among others, the key enzyme for nitrogen-storage, N-acetyl-glutamate kinase (NAGK), and the co-activator of the global nitrogen-trascription factor NtcA, the PII-interacting protein-X (PipX). One of the remarkable PII variants from Synechococcus elongatus PCC 7942 that yielded mechanistic insights in PII-NAGK interaction, is the NAGK-superactivating variant I86N. Here we studied its interaction with PipX. Another critical residue is Lys58, forming a salt-bridge with 2-oxoglutarate in a PII-ATP-2-oxoglutarate complex. Here, we show that Lys58 of PII protein is a key residue for mediating PII interactions. The K58N mutation not only causes the loss of 2-oxogluterate binding but also strongly impairs binding of ADP, NAGK and PipX. Remarkably, the exchange of the nearby Leu56 to Lys in the K58N variant partially compensates for the loss of K58. This study demonstrates the potential of creating custom tailored PII variants to modulate metabolism.
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Affiliation(s)
- Khaled A Selim
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Organismic Interactions, Eberhard Karls University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany.
| | - Michael Haffner
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Organismic Interactions, Eberhard Karls University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Björn Watzer
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Organismic Interactions, Eberhard Karls University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine, Department of Organismic Interactions, Eberhard Karls University of Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
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Moure VR, Siöberg CLB, Valdameri G, Nji E, Oliveira MAS, Gerdhardt ECM, Pedrosa FO, Mitchell DA, Seefeldt LC, Huergo LF, Högbom M, Nordlund S, Souza EM. The ammonium transporter AmtB and the PII signal transduction protein GlnZ are required to inhibit DraG in Azospirillum brasilense. FEBS J 2019; 286:1214-1229. [PMID: 30633437 DOI: 10.1111/febs.14745] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 11/04/2018] [Accepted: 01/09/2019] [Indexed: 01/15/2023]
Abstract
The ammonium-dependent posttranslational regulation of nitrogenase activity in Azospirillum brasilense requires dinitrogenase reductase ADP-ribosyl transferase (DraT) and dinitrogenase reductase ADP-glycohydrolase (DraG). These enzymes are reciprocally regulated by interaction with the PII proteins, GlnB and GlnZ. In this study, purified ADP-ribosylated Fe-protein was used as substrate to study the mechanism involved in the regulation of A. brasilense DraG in vitro. The data show that DraG is partially inhibited by GlnZ and that DraG inhibition is further enhanced by the simultaneous presence of GlnZ and AmtB. These results are the first to demonstrate experimentally that DraG inactivation requires the formation of a ternary DraG-GlnZ-AmtB complex in vitro. Previous structural data have revealed that when the DraG-GlnZ complex associates with AmtB, the flexible T-loops of the trimeric GlnZ bind to AmtB and become rigid; these molecular events stabilize the DraG-GlnZ complex, resulting in DraG inactivation. To determine whether restraining the flexibility of the GlnZ T-loops is a limiting factor in DraG inhibition, we used a GlnZ variant that carries a partial deletion of the T-loop (GlnZΔ42-54). However, although the GlnZΔ42-54 variant was more effective in inhibiting DraG in vitro, it bound to DraG with a slightly lower affinity than does wild-type GlnZ and was not competent to completely inhibit DraG activity either in vitro or in vivo. We, therefore, conclude that the formation of a ternary complex between DraG-GlnZ-AmtB is necessary for the inactivation of DraG.
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Affiliation(s)
- Vivian R Moure
- Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Catrine L B Siöberg
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Sweden
| | - Glaucio Valdameri
- Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Emmanuel Nji
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Sweden
| | - Marco Aurelio S Oliveira
- Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Edileusa C M Gerdhardt
- Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Fabio O Pedrosa
- Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - David A Mitchell
- Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
| | - Lance C Seefeldt
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, USA
| | - Luciano F Huergo
- Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil.,Setor Litoral, Universidade Federal do Paraná, Matinhos, Brazil
| | - Martin Högbom
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Sweden
| | - Stefan Nordlund
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, Sweden
| | - Emanuel M Souza
- Instituto Nacional de Ciência e Tecnologia da Fixação Biológica de Nitrogênio, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Brazil
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The deuridylylation activity of Herbaspirillum seropedicae GlnD protein is regulated by the glutamine:2-oxoglutarate ratio. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:1216-1223. [DOI: 10.1016/j.bbapap.2018.09.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 09/22/2018] [Accepted: 09/25/2018] [Indexed: 11/21/2022]
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The PII signaling protein from red algae represents an evolutionary link between cyanobacterial and Chloroplastida PII proteins. Sci Rep 2018; 8:790. [PMID: 29335634 PMCID: PMC5768801 DOI: 10.1038/s41598-017-19046-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 12/15/2017] [Indexed: 11/16/2022] Open
Abstract
PII superfamily consists of widespread signal transduction proteins found in all domains of life. Whereas they are well-studied in Archaea, Bacteria and Chloroplastida, no PII homolog has been analyzed in Rhodophyta (red algae), where PII is encoded by a chloroplast localized glnB gene. Here, we characterized relevant sensory properties of PII from the red alga Porphyra purpurea (PpPII) in comparison to PII proteins from different phyla of oxygenic phototrophs (cyanobacteria, Chlamydomonas and Physcomitrella) to assess evolutionary conservation versus adaptive properties. Like its cyanobacterial counterparts, PpPII binds ATP/ADP and 2-oxoglutarate in synergy with ATP. However, green algae and land plant PII proteins lost the ability to bind ADP. In contrast to PII proteins from green algae and land plants, PpPII enhances the activity of N-acetyl-L-glutamate kinase (NAGK) and relieves it from feedback inhibition by arginine in a glutamine-independent manner. Like PII from Chloroplastida, PpPII is not able to interact with the cyanobacterial transcriptional co-activator PipX. These data emphasize the conserved role of NAGK as a major PII-interactor throughout the evolution of oxygenic phototrophs, and confirms the specific role of PipX for cyanobacteria. Our results highlight the PII signaling system in red algae as an evolutionary intermediate between Cyanobacteria and Chlorophyta.
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Hauf W, Schmid K, Gerhardt ECM, Huergo LF, Forchhammer K. Interaction of the Nitrogen Regulatory Protein GlnB (P II) with Biotin Carboxyl Carrier Protein (BCCP) Controls Acetyl-CoA Levels in the Cyanobacterium Synechocystis sp. PCC 6803. Front Microbiol 2016; 7:1700. [PMID: 27833596 PMCID: PMC5080355 DOI: 10.3389/fmicb.2016.01700] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/12/2016] [Indexed: 11/13/2022] Open
Abstract
The family of PII signal transduction proteins (members GlnB, GlnK, NifI) plays key roles in various cellular processes related to nitrogen metabolism at different functional levels. Recent studies implied that PII proteins may also be involved in the regulation of fatty acid metabolism, since GlnB proteins from Proteobacteria and from Arabidopsis thaliana were shown to interact with biotin carboxyl carrier protein (BCCP) of acetyl-CoA carboxylase (ACC). In case of Escherichia coli ACCase, this interaction reduces the kcat of acetyl-CoA carboxylation, which should have a marked impact on the acetyl-CoA metabolism. In this study we show that the PII protein of a unicellular cyanobacterium inhibits the biosynthetic activity of E. coli ACC and also interacts with cyanobacterial BCCP in an ATP and 2-oxoglutarate dependent manner. In a PII mutant strain of Synechocystis strain PCC 6803, the lacking control leads to reduced acetyl-CoA levels, slightly increased levels of fatty acids and formation of lipid bodies as well as an altered fatty acid composition.
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Affiliation(s)
- Waldemar Hauf
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen Tübingen, Germany
| | - Katharina Schmid
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen Tübingen, Germany
| | - Edileusa C M Gerhardt
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná Curitiba, Brazil
| | - Luciano F Huergo
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal do ParanáCuritiba, Brazil; Setor Litoral, Universidade Federal do ParanáMatinhos, Brazil
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen Tübingen, Germany
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Abstract
The metabolite 2-oxoglutarate (also known as α-ketoglutarate, 2-ketoglutaric acid, or oxoglutaric acid) lies at the intersection between the carbon and nitrogen metabolic pathways. This compound is a key intermediate of one of the most fundamental biochemical pathways in carbon metabolism, the tricarboxylic acid (TCA) cycle. In addition, 2-oxoglutarate also acts as the major carbon skeleton for nitrogen-assimilatory reactions. Experimental data support the conclusion that intracellular levels of 2-oxoglutarate fluctuate according to nitrogen and carbon availability. This review summarizes how nature has capitalized on the ability of 2-oxoglutarate to reflect cellular nutritional status through evolution of a variety of 2-oxoglutarate-sensing regulatory proteins. The number of metabolic pathways known to be regulated by 2-oxoglutarate levels has increased significantly in recent years. The signaling properties of 2-oxoglutarate are highlighted by the fact that this metabolite regulates the synthesis of the well-established master signaling molecule, cyclic AMP (cAMP), in Escherichia coli.
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Forchhammer K, Lüddecke J. Sensory properties of the PII signalling protein family. FEBS J 2015; 283:425-37. [PMID: 26527104 DOI: 10.1111/febs.13584] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 10/06/2015] [Accepted: 10/28/2015] [Indexed: 11/30/2022]
Abstract
PII 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 PII 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, PII 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 PII -receptor interaction, leading to a highly sophisticated signalling network organized by PII . Altogether, it appears that PII 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 PII function, several bacterial PII proteins may transmit a signal of the cellular glutamine status via covalent modification. Remarkably, during the evolution of plant chloroplasts, glutamine signalling by PII 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 PII proteins with one of its targets, the arginine biosynthetic enzyme N-acetyl-glutamate kinase, glutamine-dependent.
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Affiliation(s)
- Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen, Germany
| | - Jan Lüddecke
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard-Karls-Universität Tübingen, Germany
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Oliveira MAS, Gerhardt ECM, Huergo LF, Souza EM, Pedrosa FO, Chubatsu LS. 2-Oxoglutarate levels control adenosine nucleotide binding by Herbaspirillum seropedicae PII proteins. FEBS J 2015; 282:4797-809. [PMID: 26433003 DOI: 10.1111/febs.13542] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 09/22/2015] [Accepted: 09/29/2015] [Indexed: 11/29/2022]
Abstract
Nitrogen metabolism in Proteobacteria is controlled by the Ntr system, in which PII proteins play a pivotal role, controlling the activity of target proteins in response to the metabolic state of the cell. Characterization of the binding of molecular effectors to these proteins can provide information about their regulation. Here, the binding of ATP, ADP and 2-oxoglutarate (2-OG) to the Herbaspirillum seropedicae PII proteins, GlnB and GlnK, was characterized using isothermal titration calorimetry. Results show that these proteins can bind three molecules of ATP, ADP and 2-OG with homotropic negative cooperativity, and 2-OG binding stabilizes the binding of ATP. Results also show that the affinity of uridylylated forms of GlnB and GlnK for nucleotides is significantly lower than that of the nonuridylylated proteins. Furthermore, fluctuations in the intracellular concentration of 2-OG in response to nitrogen availability are shown. Results suggest that under nitrogen-limiting conditions, PII proteins tend to bind ATP and 2-OG. By contrast, after an ammonium shock, a decrease in the 2-OG concentration is observed causing a decrease in the affinity of PII proteins for ATP. This phenomenon may facilitate the exchange of ATP for ADP on the ligand-binding pocket of PII proteins, thus it is likely that under low ammonium, low 2-OG levels would favor the ADP-bound state.
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Affiliation(s)
- Marco A S Oliveira
- Department of Biochemistry and Molecular Biology, Universidade Federal do Parana, Curitiba, Brazil
| | - Edileusa C M Gerhardt
- Department of Biochemistry and Molecular Biology, Universidade Federal do Parana, Curitiba, Brazil
| | - Luciano F Huergo
- Department of Biochemistry and Molecular Biology, Universidade Federal do Parana, Curitiba, Brazil
| | - Emanuel M Souza
- Department of Biochemistry and Molecular Biology, Universidade Federal do Parana, Curitiba, Brazil
| | - Fábio O Pedrosa
- Department of Biochemistry and Molecular Biology, Universidade Federal do Parana, Curitiba, Brazil
| | - Leda S Chubatsu
- Department of Biochemistry and Molecular Biology, Universidade Federal do Parana, Curitiba, Brazil
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Lüddecke J, Forchhammer K. Energy Sensing versus 2-Oxoglutarate Dependent ATPase Switch in the Control of Synechococcus PII Interaction with Its Targets NAGK and PipX. PLoS One 2015; 10:e0137114. [PMID: 26317540 PMCID: PMC4552645 DOI: 10.1371/journal.pone.0137114] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 08/07/2015] [Indexed: 12/20/2022] Open
Abstract
PII proteins constitute a superfamily of highly conserved signaling devices, common in all domains of life. Through binding of the metabolites ATP, ADP and 2-oxoglutarate (2-OG), they undergo conformational changes which allow them to regulate a variety of target proteins including enzymes, transport proteins and transcription factors. But, in reverse, these target proteins also modulate the metabolite sensing properties of PII, as has been recently shown. We used this effect to refine our PII based Förster resonance energy transfer (FRET) sensor and amplify its sensitivity towards ADP. With this enhanced sensor setup we addressed the question whether the PII protein from the model organism Synechococcus elongatus autonomously switches into the ADP conformation through ATPase activity as proposed in a recently published model. The present study disproves ATPase activity as a relevant mechanism for the transition of PII into the ADP state. In the absence of 2-OG, only the ATP/ADP ratio and concentration of ADP directs the competitive interaction of PII with two targets, one of which preferentially binds PII in the ATP-state, the other in the ADP-state.
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Affiliation(s)
- Jan Lüddecke
- Interfaculty Institute for Microbiology and Infection Medicine, Division Organismic Interactions, University of Tübingen, Auf der Morgenstelle 28, D-72076, Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute for Microbiology and Infection Medicine, Division Organismic Interactions, University of Tübingen, Auf der Morgenstelle 28, D-72076, Tübingen, Germany
- * E-mail:
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Merrick M. Post-translational modification of P II signal transduction proteins. Front Microbiol 2015; 5:763. [PMID: 25610437 PMCID: PMC4285133 DOI: 10.3389/fmicb.2014.00763] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 12/15/2014] [Indexed: 11/13/2022] Open
Abstract
The PII proteins constitute one of the most widely distributed families of signal transduction proteins in nature. They are pivotal players in the control of nitrogen metabolism in bacteria and archaea, and are also found in the plastids of plants. Quite remarkably PII proteins control the activities of a diverse range of enzymes, transcription factors and membrane transport proteins, and in all known cases they achieve their regulatory effect by direct interaction with their target. PII proteins in the Proteobacteria and the Actinobacteria are subject to post-translational modification by uridylylation or adenylylation respectively, whilst in some Cyanobacteria they can be modified by phosphorylation. In all these cases the protein's modification state is influenced by the cellular nitrogen status and is thought to regulate its activity. However, in many organisms there is no evidence for modification of PII proteins and indeed the ability of these proteins to respond to the cellular nitrogen status is fundamentally independent of post-translational modification. In this review we explore the role of post-translational modification in PII proteins in the light of recent studies.
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Affiliation(s)
- Mike Merrick
- Department of Molecular Microbiology, John Innes Centre Norwich, UK
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Inaba J, Thornton J, Huergo LF, Monteiro RA, Klassen G, Pedrosa FDO, Merrick M, de Souza EM. Mutational analysis of GlnB residues critical for NifA activation in Azospirillum brasilense. Microbiol Res 2014; 171:65-72. [PMID: 25644954 DOI: 10.1016/j.micres.2014.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 12/08/2014] [Accepted: 12/14/2014] [Indexed: 11/28/2022]
Abstract
PII proteins are signal transduction that sense cellular nitrogen status and relay this signals to other targets. Azospirillum brasilense is a nitrogen fixing bacterium, which associates with grasses and cereals promoting beneficial effects on plant growth and crop yields. A. brasilense contains two PII encoding genes, named glnB and glnZ. In this paper, glnB was mutagenised in order to identify amino acid residues involved in GlnB signaling. Two variants were obtained by random mutagenesis, GlnBL13P and GlnBV100A and a site directed mutant, GlnBY51F, was obtained. Their ability to complement nitrogenase activity of glnB mutant strains of A. brasilense were determined. The variant proteins were also overexpressed in Escherichia coli, purified and characterized biochemically. None of the GlnB variant forms was able to restore nitrogenase activity in glnB mutant strains of A. brasilense LFH3 and 7628. The purified GlnBY51F and GlnBL13P proteins could not be uridylylated by GlnD, whereas GlnBV100A was uridylylated but at only 20% of the rate for wild type GlnB. Biochemical and computational analyses suggest that residue Leu13, located in the α helix 1 of GlnB, is important to maintain GlnB trimeric structure and function. The substitution V100A led to a lower affinity for ATP binding. Together the results suggest that NifA activation requires uridylylated GlnB bound to ATP.
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Affiliation(s)
- Juliana Inaba
- Department of Chemistry, Universidade Estadual de Ponta Grossa, Av. Gal. Carlos Cavalcanti, 4748, CEP 84030-900 Ponta Grossa, PR, Brazil.
| | - Jeremy Thornton
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom.
| | - Luciano Fernandes Huergo
- Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, CP 19046, CEP 81531-990 Curitiba, PR, Brazil.
| | - Rose Adele Monteiro
- Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, CP 19046, CEP 81531-990 Curitiba, PR, Brazil.
| | - Giseli Klassen
- Department of Basic Pathology, Universidade Federal do Paraná, CP 19046, CEP 81531-990 Curitiba, PR, Brazil.
| | - Fábio de Oliveira Pedrosa
- Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, CP 19046, CEP 81531-990 Curitiba, PR, Brazil.
| | - Mike Merrick
- Department of Molecular Microbiology, John Innes Centre, Norwich NR4 7UH, United Kingdom.
| | - Emanuel Maltempi de Souza
- Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, CP 19046, CEP 81531-990 Curitiba, PR, Brazil.
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