1
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Farkas P, Fitzpatrick TB. Two pyridoxal phosphate homeostasis proteins are essential for management of the coenzyme pyridoxal 5'-phosphate in Arabidopsis. THE PLANT CELL 2024; 36:3689-3708. [PMID: 38954500 PMCID: PMC11371154 DOI: 10.1093/plcell/koae176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/17/2024] [Accepted: 06/10/2024] [Indexed: 07/04/2024]
Abstract
Coenzyme management is important for homeostasis of the pool of active metabolic enzymes. The coenzyme pyridoxal 5'-phosphate (PLP) is involved in diverse enzyme reactions including amino acid and hormone metabolism. Regulatory proteins that contribute to PLP homeostasis remain to be explored in plants. Here, we demonstrate the importance of proteins annotated as PLP homeostasis proteins (PLPHPs) for controlling PLP in Arabidopsis (Arabidopsis thaliana). A systematic analysis indicates that while most organisms across kingdoms have a single PLPHP homolog, Angiosperms have two. PLPHPs from Arabidopsis bind PLP and exist as monomers, in contrast to reported PLP-dependent enzymes, which exist as multimers. Disrupting the function of both PLPHP homologs perturbs vitamin B6 (pyridoxine) content, inducing a PLP deficit accompanied by light hypersensitive root growth, unlike PLP biosynthesis mutants. Micrografting studies show that the PLP deficit can be relieved distally between shoots and roots. Chemical treatments probing PLP-dependent reactions, notably those for auxin and ethylene, provide evidence that PLPHPs function in the dynamic management of PLP. Assays in vitro show that Arabidopsis PLPHP can coordinate PLP transfer and withdrawal from other enzymes. This study thus expands our knowledge of vitamin B6 biology and highlights the importance of PLP coenzyme homeostasis in plants.
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Affiliation(s)
- Peter Farkas
- Vitamins & Environmental Stress Responses in Plants, Department of Plant Sciences, University of Geneva, 1211 Geneva, Switzerland
| | - Teresa B Fitzpatrick
- Vitamins & Environmental Stress Responses in Plants, Department of Plant Sciences, University of Geneva, 1211 Geneva, Switzerland
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2
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Aleshin VA, Bunik VI. Protein-Protein Interfaces as Druggable Targets: A Common Motif of the Pyridoxal-5'-Phosphate-Dependent Enzymes to Receive the Coenzyme from Its Producers. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1022-1033. [PMID: 37751871 DOI: 10.1134/s0006297923070131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/22/2023] [Accepted: 04/10/2023] [Indexed: 09/28/2023]
Abstract
Pyridoxal-5'-phosphate (PLP), a phosphorylated form of vitamin B6, acts as a coenzyme for numerous reactions, including those changed in cancer and/or associated with the disease prognosis. Since highly reactive PLP can modify cellular proteins, it is hypothesized to be directly transferred from its donors to acceptors. Our goal is to validate the hypothesis by finding common motif(s) in the multitude of PLP-dependent enzymes for binding the limited number of PLP donors, namely pyridoxal kinase (PdxK), pyridox(am)in-5'-phosphate oxidase (PNPO), and PLP-binding protein (PLPBP). Experimentally confirmed interactions between the PLP donors and acceptors reveal that PdxK and PNPO interact with the most abundant PLP acceptors belonging to structural folds I and II, while PLPBP - with those belonging to folds III and V. Aligning sequences and 3D structures of the identified interactors of PdxK and PNPO, we have identified a common motif in the PLP-dependent enzymes of folds I and II. The motif extends from the enzyme surface to the neighborhood of the PLP binding site, represented by an exposed alfa-helix, a partially buried beta-strand, and residual loops. Pathogenicity of mutations in the human PLP-dependent enzymes within or in the vicinity of the motif, but outside of the active sites, supports functional significance of the motif that may provide an interface for the direct transfer of PLP from the sites of its synthesis to those of coenzyme binding. The enzyme-specific amino acid residues of the common motif may be useful to develop selective inhibitors blocking PLP delivery to the PLP-dependent enzymes critical for proliferation of malignant cells.
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Affiliation(s)
- Vasily A Aleshin
- Department of Biokinetics, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Department of Biochemistry, Sechenov University, Moscow, 119048, Russia
| | - Victoria I Bunik
- Department of Biokinetics, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
- Department of Biochemistry, Sechenov University, Moscow, 119048, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia
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3
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Llop A, Labella JI, Borisova M, Forchhammer K, Selim KA, Contreras A. Pleiotropic effects of PipX, PipY, or RelQ overexpression on growth, cell size, photosynthesis, and polyphosphate accumulation in the cyanobacterium Synechococcus elongatus PCC7942. Front Microbiol 2023; 14:1141775. [PMID: 37007489 PMCID: PMC10060972 DOI: 10.3389/fmicb.2023.1141775] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 02/23/2023] [Indexed: 03/18/2023] Open
Abstract
The cyanobacterial protein PipY belongs to the Pyridoxal-phosphate (PLP)-binding proteins (PLPBP/COG0325) family of pyridoxal-phosphate-binding proteins, which are represented in all three domains of life. These proteins share a high degree of sequence conservation, appear to have purely regulatory functions, and are involved in the homeostasis of vitamin B6 vitamers and amino/keto acids. Intriguingly, the genomic context of the pipY gene in cyanobacteria connects PipY with PipX, a protein involved in signaling the intracellular energy status and carbon-to-nitrogen balance. PipX regulates its cellular targets via protein–protein interactions. These targets include the PII signaling protein, the ribosome assembly GTPase EngA, and the transcriptional regulators NtcA and PlmA. PipX is thus involved in the transmission of multiple signals that are relevant for metabolic homeostasis and stress responses in cyanobacteria, but the exact function of PipY is still elusive. Preliminary data indicated that PipY might also be involved in signaling pathways related to the stringent stress response, a pathway that can be induced in the unicellular cyanobacterium Synechococcus elongatus PCC7942 by overexpression of the (p)ppGpp synthase, RelQ. To get insights into the cellular functions of PipY, we performed a comparative study of PipX, PipY, or RelQ overexpression in S. elongatus PCC7942. Overexpression of PipY or RelQ caused similar phenotypic responses, such as growth arrest, loss of photosynthetic activity and viability, increased cell size, and accumulation of large polyphosphate granules. In contrast, PipX overexpression decreased cell length, indicating that PipX and PipY play antagonistic roles on cell elongation or cell division. Since ppGpp levels were not induced by overexpression of PipY or PipX, it is apparent that the production of polyphosphate in cyanobacteria does not require induction of the stringent response.
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Affiliation(s)
- Antonio Llop
- Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
- Interfaculty Institute for Microbiology and Infection Medicine, Organismic Interactions Department, Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Tübingen, Germany
| | - Jose I. Labella
- Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
| | - Marina Borisova
- Interfaculty Institute for Microbiology and Infection Medicine, Organismic Interactions Department, Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute for Microbiology and Infection Medicine, Organismic Interactions Department, Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Tübingen, Germany
| | - Khaled A. Selim
- Interfaculty Institute for Microbiology and Infection Medicine, Organismic Interactions Department, Cluster of Excellence 'Controlling Microbes to Fight Infections', University of Tübingen, Tübingen, Germany
| | - Asunción Contreras
- Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
- *Correspondence: Asunción Contreras,
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4
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Tramonti A, Ghatge MS, Babor JT, Musayev FN, di Salvo ML, Barile A, Colotti G, Giorgi A, Paredes SD, Donkor AK, Al Mughram MH, de Crécy‐Lagard V, Safo MK, Contestabile R. Characterization of the Escherichia coli pyridoxal 5'-phosphate homeostasis protein (YggS): Role of lysine residues in PLP binding and protein stability. Protein Sci 2022; 31:e4471. [PMID: 36218140 PMCID: PMC9601805 DOI: 10.1002/pro.4471] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/04/2022] [Accepted: 07/25/2022] [Indexed: 02/04/2023]
Abstract
The pyridoxal 5'-phosphate (PLP) homeostasis protein (PLPHP) is a ubiquitous member of the COG0325 family with apparently no catalytic activity. Although the actual cellular role of this protein is unknown, it has been observed that mutations of the PLPHP encoding gene affect the activity of PLP-dependent enzymes, B6 vitamers and amino acid levels. Here we report a detailed characterization of the Escherichia coli ortholog of PLPHP (YggS) with respect to its PLP binding and transfer properties, stability, and structure. YggS binds PLP very tightly and is able to slowly transfer it to a model PLP-dependent enzyme, serine hydroxymethyltransferase. PLP binding to YggS elicits a conformational/flexibility change in the protein structure that is detectable in solution but not in crystals. We serendipitously discovered that the K36A variant of YggS, affecting the lysine residue that binds PLP at the active site, is able to bind PLP covalently. This observation led us to recognize that a number of lysine residues, located at the entrance of the active site, can replace Lys36 in its PLP binding role. These lysines form a cluster of charged residues that affect protein stability and conformation, playing an important role in PLP binding and possibly in YggS function.
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Affiliation(s)
- Angela Tramonti
- Istituto di Biologia e Patologia MolecolariConsiglio Nazionale delle RicercheRomeItaly
- Istituto Pasteur Italia‐Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Mohini S. Ghatge
- Institute for Structural Biology, Drug Discovery and Development, Department of Medicinal ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Jill T. Babor
- Department of Microbiology and Cell ScienceUniversity of FloridaGainsvilleFloridaUSA
| | - Faik N. Musayev
- Institute for Structural Biology, Drug Discovery and Development, Department of Medicinal ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Martino Luigi di Salvo
- Istituto Pasteur Italia‐Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Anna Barile
- Istituto di Biologia e Patologia MolecolariConsiglio Nazionale delle RicercheRomeItaly
- Istituto Pasteur Italia‐Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Gianni Colotti
- Istituto di Biologia e Patologia MolecolariConsiglio Nazionale delle RicercheRomeItaly
| | - Alessandra Giorgi
- Istituto Pasteur Italia‐Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
| | - Steven D. Paredes
- Institute for Structural Biology, Drug Discovery and Development, Department of Medicinal ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Akua K. Donkor
- Institute for Structural Biology, Drug Discovery and Development, Department of Medicinal ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Mohammed H. Al Mughram
- Institute for Structural Biology, Drug Discovery and Development, Department of Medicinal ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Valérie de Crécy‐Lagard
- Department of Microbiology and Cell ScienceUniversity of FloridaGainsvilleFloridaUSA
- Genetics InstituteUniversity of FloridaGainesvilleFloridaUSA
| | - Martin K. Safo
- Institute for Structural Biology, Drug Discovery and Development, Department of Medicinal ChemistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Roberto Contestabile
- Istituto Pasteur Italia‐Fondazione Cenci Bolognetti and Dipartimento di Scienze Biochimiche “A. Rossi Fanelli”Sapienza Università di RomaRomeItaly
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5
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The Conserved Family of the Pyridoxal Phosphate-Binding Protein (PLPBP) and Its Cyanobacterial Paradigm PipY. Life (Basel) 2022; 12:life12101622. [PMID: 36295057 PMCID: PMC9605639 DOI: 10.3390/life12101622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/05/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022] Open
Abstract
The PLPBP family of pyridoxal phosphate-binding proteins has a high degree of sequence conservation and is represented in all three domains of life. PLPBP members, of which a few representatives have been studied in different contexts, are single-domain proteins with no known enzymatic activity that exhibit the fold type III of PLP-holoenzymes, consisting in an α/β barrel (TIM-barrel), where the PLP cofactor is solvent-exposed. Despite the constant presence of cofactor PLP (a key catalytic element in PLP enzymes), PLPBP family members appear to have purely regulatory functions affecting the homeostasis of vitamin B6 vitamers and amino/keto acids. Perturbation of these metabolites and pleiotropic phenotypes have been reported in bacteria and zebrafish after PLPBP gene inactivation as well as in patients with vitamin B6-dependent epilepsy that results from loss-of-function mutations at the PLPBP. Here, we review information gathered from diverse studies and biological systems, emphasizing the structural and functional conservation of the PLPBP members and discussing the informative nature of model systems and experimental approaches. In this context, the relatively high level of structural and functional characterization of PipY from Synechococcus elongatus PCC 7942 provides a unique opportunity to investigate the PLPBP roles in the context of a signaling pathway conserved in cyanobacteria.
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6
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He S, Chen Y, Wang L, Bai X, Bu T, Zhang J, Lu M, Ha NC, Quan C, Nam KH, Xu Y. Structural and Functional Analysis of the Pyridoxal Phosphate Homeostasis Protein YggS from Fusobacterium nucleatum. Molecules 2022; 27:molecules27154781. [PMID: 35897955 PMCID: PMC9332261 DOI: 10.3390/molecules27154781] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/15/2022] [Accepted: 07/23/2022] [Indexed: 11/16/2022] Open
Abstract
Pyridoxal 5′-phosphate (PLP) is the active form of vitamin B6, but it is highly reactive and poisonous in its free form. YggS is a PLP-binding protein found in bacteria and humans that mediates PLP homeostasis by delivering PLP to target enzymes or by performing a protective function. Several biochemical and structural studies of YggS have been reported, but the mechanism by which YggS recognizes PLP has not been fully elucidated. Here, we report a functional and structural analysis of YggS from Fusobacterium nucleatum (FnYggS). The PLP molecule could bind to native FnYggS, but no PLP binding was observed for selenomethionine (SeMet)-derivatized FnYggS. The crystal structure of FnYggS showed a type III TIM barrel fold, exhibiting structural homology with several other PLP-dependent enzymes. Although FnYggS exhibited low (<35%) amino acid sequence similarity with previously studied YggS proteins, its overall structure and PLP-binding site were highly conserved. In the PLP-binding site of FnYggS, the sulfate ion was coordinated by the conserved residues Ser201, Gly218, and Thr219, which were positioned to provide the binding moiety for the phosphate group of PLP. The mutagenesis study showed that the conserved Ser201 residue in FnYggS was the key residue for PLP binding. These results will expand the knowledge of the molecular properties and function of the YggS family.
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Affiliation(s)
- Shanru He
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, China; (S.H.); (Y.C.); (L.W.); (X.B.); (T.B.); (J.Z.)
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian 116600, China
| | - Yuanyuan Chen
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, China; (S.H.); (Y.C.); (L.W.); (X.B.); (T.B.); (J.Z.)
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian 116600, China
| | - Lulu Wang
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, China; (S.H.); (Y.C.); (L.W.); (X.B.); (T.B.); (J.Z.)
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian 116600, China
- School of Life Science and Biotechnology, Dalian University of Technology, No. 2 Linggong Road, Dalian 116024, China
| | - Xue Bai
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, China; (S.H.); (Y.C.); (L.W.); (X.B.); (T.B.); (J.Z.)
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian 116600, China
| | - Tingting Bu
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, China; (S.H.); (Y.C.); (L.W.); (X.B.); (T.B.); (J.Z.)
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian 116600, China
| | - Jie Zhang
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, China; (S.H.); (Y.C.); (L.W.); (X.B.); (T.B.); (J.Z.)
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian 116600, China
| | - Ming Lu
- Shandong Provincial Key Laboratory of Energy Genetics, Key Laboratory of Biofuel, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China;
| | - Nam-Chul Ha
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Gwanak-gu, Seoul 00826, Korea;
| | - Chunshan Quan
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, China; (S.H.); (Y.C.); (L.W.); (X.B.); (T.B.); (J.Z.)
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian 116600, China
- Correspondence: (C.Q.); (K.H.N.); (Y.X.)
| | - Ki Hyun Nam
- Department of Life Science, Pohang University of Science and Technology, Pohang 37673, Korea
- POSTECH Biotech Center, Pohang University of Science and Technology, Pohang 37673, Korea
- Correspondence: (C.Q.); (K.H.N.); (Y.X.)
| | - Yongbin Xu
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, China; (S.H.); (Y.C.); (L.W.); (X.B.); (T.B.); (J.Z.)
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education, College of Life Science, Dalian Minzu University, Dalian 116600, China
- Correspondence: (C.Q.); (K.H.N.); (Y.X.)
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7
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Ito T. Role of the conserved pyridoxal 5'-phosphate-binding protein YggS/PLPBP in vitamin B6 and amino acid homeostasis. Biosci Biotechnol Biochem 2022; 86:1183-1191. [PMID: 35803498 DOI: 10.1093/bbb/zbac113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 06/30/2022] [Indexed: 11/14/2022]
Abstract
The YggS/PLPBP protein (also called COG0325 or PLPHP) is a conserved pyridoxal 5'-phosphate (PLP)-binding protein present in all three domains of life. Recent studies have demonstrated that disruption or mutation of this protein has multifaceted effects in various organisms, including vitamin B6-dependent epilepsy in humans. In Escherichia coli, disruption of this protein-encoded by yggS-perturbs Thr-Ile/Val metabolism, one-carbon metabolism, coenzyme A synthesis, and vitamin B6 homeostasis. This protein is critical for maintaining low levels of pyridoxine 5'-phosphate (PNP) in various organisms. In the yggS-deficient E. coli strain, inhibition of PLP-dependent enzymes, such as the glycine cleavage system by PNP is the root cause of metabolic perturbation. Our data suggest that the YggS/PLPBP protein may be involved in the balancing of B6 vitamers by mediating efficient turnover of protein-bound B6 vitamers. This paper reviews recent findings on the function of the YggS/PLPBP protein.
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Affiliation(s)
- Tomokazu Ito
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi, Japan
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8
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Wang Y, Zhao Y, Xia L, Chen L, Liao Y, Chen B, Liu Y, Gong W, Tian Y, Hu B. yggS Encoding Pyridoxal 5'-Phosphate Binding Protein Is Required for Acidovorax citrulli Virulence. Front Microbiol 2022; 12:783862. [PMID: 35087487 PMCID: PMC8787154 DOI: 10.3389/fmicb.2021.783862] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/06/2021] [Indexed: 11/26/2022] Open
Abstract
Bacterial fruit blotch, caused by seed-borne pathogen Acidovorax citrulli, poses a serious threat to the production of cucurbits globally. Although the disease can cause substantial economic losses, limited information is available about the molecular mechanisms of virulence. This study identified that, a random transposon insertion mutant impaired in the ability to elicit a hypersensitive response on tobacco. The disrupted gene in this mutant was determined to be Aave_0638, which is predicted to encode a YggS family pyridoxal phosphate-dependent enzyme. YggS is a highly conserved protein among multiple organisms, and is responsible for maintaining the homeostasis of pyridoxal 5′-phosphate and amino acids in cells. yggS deletion mutant of A. citrulli strain XjL12 displayed attenuated virulence, delayed hypersensitive response, less tolerance to H2O2 and pyridoxine, increased sensitivity to antibiotic β-chloro-D-alanine, and reduced swimming. In addition, RNA-Seq analysis demonstrated that yggS was involved in regulating the expression of certain pathogenicity-associated genes related to secretion, motility, quorum sensing and oxidative stress response. Importantly, YggS significantly affected type III secretion system and its effectors in vitro. Collectively, our results suggest that YggS is indispensable for A.citrulli virulence and expands the role of YggS in the biological processes.
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Affiliation(s)
- Yuanjie Wang
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing, China
| | - Yuqiang Zhao
- Institute of Botany, Jiangsu Province and Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-sen), Nanjing, China
| | - Liming Xia
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing, China
| | - Lin Chen
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing, China
| | - Yajie Liao
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing, China
| | - Baohui Chen
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing, China
| | - Yiyang Liu
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing, China
| | - Weirong Gong
- Plant Protection and Quarantine Station of Province, Nanjing, China
| | - Yanli Tian
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing, China
| | - Baishi Hu
- College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing, China
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9
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Mechanism of pyridoxine 5'-phosphate accumulation in PLPBP protein-deficiency. J Bacteriol 2022; 204:e0052121. [PMID: 34978460 DOI: 10.1128/jb.00521-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pyridoxal 5'-phosphate (PLP)-binding protein (PLPBP) plays an important role in vitamin B6 homeostasis. Loss of this protein in organisms such as Escherichia coli and humans disrupts the vitamin B6 pool and induces intracellular accumulation of pyridoxine 5'-phosphate (PNP), which is normally undetectable in wild-type cells. The accumulated PNP could affect diverse metabolic systems through inhibition of some PLP-dependent enzymes. In this study, we investigated the as yet unclear mechanism of intracellular accumulation of PNP by the loss of PLPBP protein encoded by yggS in E. coli. Genetic studies using several PLPBP-deficient strains of E. coli lacking known enzyme(s) in the de novo or salvage pathway of vitamin B6, which includes pyridoxine (amine) 5'-phosphate oxidase (PNPO), PNP synthase, pyridoxal kinase, and pyridoxal reductase, demonstrated that neither the flux from the de novo pathway nor the salvage pathway solely contributed to the PNP accumulation caused by the PLPBP mutation. Studies with the strains lacking both PLPBP and PNPO suggested that PNP shares the same pool with PMP, and showed that PNP levels are impacted by PMP levels and vice versa. We show that disruption of PLPBP lead to perturb PMP homeostasis, which may result in PNP accumulation in the PLPBP-deficient strains. Importance A PLP-binding protein PLPBP from the conserved COG0325 family has recently been recognized as a key player in vitamin B6 homeostasis in various organisms. Loss of PLPBP disrupts vitamin B6 homeostasis and perturbs diverse metabolisms, including amino acid and α-keto acid metabolism. Accumulation of PNP is a characteristic phenotype of the PLPBP deficiency and is suggested to be a potential cause of the pleiotropic effects, but the mechanism of the PNP accumulation was poorly understood. In this study, we show that fluxes for PNP synthesis/metabolism are not responsible for the accumulation of PNP. Our results indicate that PLPBP is involved in the homeostasis of pyridoxamine 5'-phosphate, and its disruption may lead to the accumulation of PNP in PLPBP-deficiency.
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10
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Jerez C, Salinas P, Llop A, Cantos R, Espinosa J, Labella JI, Contreras A. Regulatory Connections Between the Cyanobacterial Factor PipX and the Ribosome Assembly GTPase EngA. Front Microbiol 2021; 12:781760. [PMID: 34956147 PMCID: PMC8696166 DOI: 10.3389/fmicb.2021.781760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/05/2021] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria, phototrophic organisms performing oxygenic photosynthesis, must adapt their metabolic processes to important environmental challenges, like those imposed by the succession of days and nights. Not surprisingly, certain regulatory proteins are found exclusively in this phylum. One of these unique proteins, PipX, provides a mechanistic link between signals of carbon/nitrogen and of energy, transduced by the signaling protein PII, and the control of gene expression by the global nitrogen regulator NtcA. PII, required for cell survival unless PipX is inactivated or downregulated, functions by protein-protein interactions with transcriptional regulators, transporters, and enzymes. PipX also functions by protein-protein interactions, and previous studies suggested the existence of additional interacting partners or included it into a relatively robust six-node synteny network with proteins apparently unrelated to the nitrogen regulation system. To investigate additional functions of PipX while providing a proof of concept for the recently developed cyanobacterial linkage network, here we analyzed the physical and regulatory interactions between PipX and an intriguing component of the PipX synteny network, the essential ribosome assembly GTPase EngA. The results provide additional insights into the functions of cyanobacterial EngA and of PipX, showing that PipX interacts with the GD1 domain of EngA in a guanosine diphosphate-dependent manner and interferes with EngA functions in Synechococcus elongatus at a low temperature, an environmentally relevant context. Therefore, this work expands the PipX interaction network and establishes a possible connection between nitrogen regulation and the translation machinery. We discuss a regulatory model integrating previous information on PII-PipX with the results presented in this work.
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Affiliation(s)
- Carmen Jerez
- Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
| | - Paloma Salinas
- Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
| | - Antonio Llop
- Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
| | - Raquel Cantos
- Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
| | - Javier Espinosa
- Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
| | - Jose I Labella
- Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
| | - Asunción Contreras
- Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Alicante, Spain
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11
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Vu HN, Downs DM. Loss of YggS (COG0325) impacts aspartate metabolism in Salmonella enterica. Mol Microbiol 2021; 116:1232-1240. [PMID: 34498310 DOI: 10.1111/mmi.14810] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 08/24/2021] [Accepted: 09/07/2021] [Indexed: 12/01/2022]
Abstract
YggS is a pyridoxal 5'-phosphate (PLP)-binding protein of the conserved COG0325 family. Despite a connection with vitamin B6 homeostasis in many species, neither a precise biochemical activity nor the molecular mechanism of how YggS contributes to cellular function has been described. In a transposon mutagenesis screen, we found that insertions in aspC (encoding a PLP-dependent aspartate aminotransferase, EC 2.6.1.1) in a Salmonella enterica strain lacking yggS caused a synthetic growth defect, which could be rescued by the addition of exogenous aspartate. Characterization of spontaneous suppressors which improved the growth of the yggS aspC double mutant suggested that this synthetic aspartate limitation was dependent on TyrB, a PLP-dependent aromatic amino acid aminotransferase (EC 2.6.1.57). Genetic and biochemical data were consistent with the hypothesis that TyrB activity was inhibited by accumulated pyridoxine 5'-phosphate and α-keto acids caused by a yggS mutation. This study provides data consistent with a working model implicating YggS in modulating concentrations of B6 vitamers via transamination.
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Affiliation(s)
- Huong N Vu
- Department of Microbiology, The University of Georgia, Athens, Georgia, USA
| | - Diana M Downs
- Department of Microbiology, The University of Georgia, Athens, Georgia, USA
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12
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Pal M, Lace B, Labrie Y, Laflamme N, Rioux N, Setty ST, Dugas M, Gosselin L, Droit A, Chrestian N, Rivest S. A founder mutation in the PLPBP gene in families from Saguenay-Lac-St-Jean region affected by a pyridoxine-dependent epilepsy. JIMD Rep 2021; 59:32-41. [PMID: 33977028 PMCID: PMC8100403 DOI: 10.1002/jmd2.12196] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 11/19/2020] [Accepted: 12/16/2020] [Indexed: 11/24/2022] Open
Abstract
Pyridoxine-dependent epilepsy (PDE) is a relatively rare subgroup of epileptic disorders. They generally present in infancy as an early onset epileptic encephalopathy or seizures, refractory to standard treatments, with rapid and variable responses to vitamin B6 treatment. Whole exome sequencing of three unrelated families identified homozygous pathogenic mutation c.370_373del, p.Asp124fs in PLPBP gene in five persons. Haplotype analysis showed a single shared profile for the affected persons and their parents, leading to a hypothesis about founder effect of the mutation in Saguenay-Lac-St-Jean region of French Canadians. All affected probands also shared one single mitochondrial haplotype T2b3 and two rare variations in the mitochondrial genome m.801A>G and m.5166A>G suggesting that a single individual female introduced PLPBP mutation c.370_373del, p.Asp124fs in Quebec. The mutation p.Asp124fs causes a severe disease phenotype with delayed myelination and cortical/subcortical brain atrophy. The most noteworthy radiological finding in this Quebec founder mutation is the presence of the temporal cysts that can be used as a marker of the disease. Also, both patients, who are alive, had a history of prenatal supplements taken by their mothers as antiemetic medication with high doses of pyridoxine. In the context of suspected PDE in patients with neonatal refractory seizures, treatment with pyridoxine and/or Pyridoxal-5-phophate has to be started immediately and continued until the results of genetic analysis received. Even with early appropriate treatment, neurological outcome of our patient is still poor.
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Affiliation(s)
- Maitou Pal
- Faculty of MedicineLaval UniversityQuébecQuébecCanada
| | - Baiba Lace
- Department of Medical GeneticsCentre Mère Enfant Soleil, Laval UniversityQuébecQuébecCanada
| | - Yvan Labrie
- Centre de recherche CHU de Québec‐ Université Laval, Laval UniversityQuébecQuébecCanada
| | - Nathalie Laflamme
- Centre de recherche CHU de Québec‐ Université Laval, Laval UniversityQuébecQuébecCanada
| | - Nadie Rioux
- Centre de recherche CHU de Québec‐ Université Laval, Laval UniversityQuébecQuébecCanada
| | - Samarth Thonta Setty
- Centre de recherche CHU de Québec‐ Université Laval, Laval UniversityQuébecQuébecCanada
| | - Marc‐Andre Dugas
- Department of PediatricsCentre Mère Enfant Soleil, Laval UniversityQuébecQuébecCanada
| | - Louise Gosselin
- Centre de recherche CHU de Québec‐ Université Laval, Laval UniversityQuébecQuébecCanada
| | - Arnaud Droit
- Centre de recherche CHU de Québec‐ Université Laval, Laval UniversityQuébecQuébecCanada
| | - Nicolas Chrestian
- Department of Pediatric Neurology, Pediatric Neuromuscular DisorderCentre Mère Enfant Soleil, Laval UniversityQuébecQuébecCanada
| | - Serge Rivest
- Centre de recherche CHU de Québec‐ Université Laval, Laval UniversityQuébecQuébecCanada
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13
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Richts B, Commichau FM. Underground metabolism facilitates the evolution of novel pathways for vitamin B6 biosynthesis. Appl Microbiol Biotechnol 2021; 105:2297-2305. [PMID: 33665688 PMCID: PMC7954711 DOI: 10.1007/s00253-021-11199-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/15/2021] [Accepted: 02/24/2021] [Indexed: 11/29/2022]
Abstract
Abstract The term vitamin B6 is a designation for the vitamers pyridoxal, pyridoxamine, pyridoxine and the respective phosphate esters pyridoxal-5′-phosphate (PLP), pyridoxamine-5′-phosphate and pyridoxine-5′-phosphate. Animals and humans are unable to synthesise vitamin B6. These organisms have to take up vitamin B6 with their diet. Therefore, vitamin B6 is of commercial interest as a food additive and for applications in the pharmaceutical industry. As yet, two naturally occurring routes for de novo synthesis of PLP are known. Both routes have been genetically engineered to obtain bacteria overproducing vitamin B6. Still, major genetic engineering efforts using the existing pathways are required for developing fermentation processes that could outcompete the chemical synthesis of vitamin B6. Recent suppressor screens using mutants of the Gram-negative and Gram-positive model bacteria Escherichia coli and Bacillus subtilis, respectively, carrying mutations in the native pathways or heterologous genes uncovered novel routes for PLP biosynthesis. These pathways consist of promiscuous enzymes and enzymes that are already involved in vitamin B6 biosynthesis. Thus, E. coli and B. subtilis contain multiple promiscuous enzymes causing a so-called underground metabolism allowing the bacteria to bypass disrupted vitamin B6 biosynthetic pathways. The suppressor screens also show the genomic plasticity of the bacteria to suppress a genetic lesion. We discuss the potential of the serendipitous pathways to serve as a starting point for the development of bacteria overproducing vitamin B6. Key points • Known vitamin B6 routes have been genetically engineered. • Underground metabolism facilitates the emergence of novel vitamin B6 biosynthetic pathways. • These pathways may be suitable to engineer bacteria overproducing vitamin B6.
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Affiliation(s)
- Björn Richts
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, Grisebachstrasse 8, 37077, Göttingen, Germany
| | - Fabian M Commichau
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Universitätsplatz 1, 01968, Senftenberg, Germany.
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14
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Heath O, Pitt J, Mandelstam S, Kuschel C, Vasudevan A, Donoghue S. Early-onset vitamin B 6-dependent epilepsy due to pathogenic PLPBP variants in a premature infant: A case report and review of the literature. JIMD Rep 2021; 58:3-11. [PMID: 33728241 PMCID: PMC7932866 DOI: 10.1002/jmd2.12183] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/26/2020] [Accepted: 10/29/2020] [Indexed: 01/17/2023] Open
Abstract
Vitamin B6-dependent epilepsies are a heterogeneous group of disorders characterized by decreased availability of the active cofactor pyridoxal-5'-phosphate (PLP). While pathogenic variants in ALDH7A1 or PNPO genes account for most cases of these disorders, biallelic pathogenic variants in PLPBP have been shown to cause a form of early onset vitamin B6-dependent epilepsy (EPVB6D). PLPBP is thought to play a role in the homeostatic regulation of vitamin B6, by supplying PLP to apoenzymes while limiting side-reaction toxicity related to excess unbound PLP. Neonatal-onset intractable seizures that respond to pyridoxine and/or PLP are a predominant feature of EPVB6D in humans. Unlike other causes of vitamin B6-dependent epilepsies; however, a specific biomarker for this disorder has yet to be identified. Here we present data from a premature infant found to have pathogenic variants in PLPBP and propose that prematurity may provide an additional clue for early consideration of this diagnosis. We discuss these findings in context of previously published genotypic, phenotypic, and metabolic data from similarly affected patients.
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Affiliation(s)
- Oliver Heath
- Department of Metabolic MedicineThe Royal Children's HospitalMelbourneAustralia
| | - James Pitt
- Department of Biochemical Genetics, Victorian Clinical Genetics ServiceMurdoch Children's Research InstituteMelbourneAustralia
- Department of PaediatricsUniversity of MelbourneMelbourneAustralia
| | - Simone Mandelstam
- Department of Medical ImagingThe Royal Children's Hospital and Murdoch Children's Research InstituteMelbourneAustralia
- Department of PaediatricsUniversity of MelbourneMelbourneAustralia
- Department of RadiologyUniversity of MelbourneMelbourneAustralia
| | - Carl Kuschel
- Department of Obstetrics and GynecologyThe Royal Women's HospitalMelbourneAustralia
| | - Anand Vasudevan
- Department of GeneticsThe Royal Women's HospitalMelbourneAustralia
| | - Sarah Donoghue
- Department of Metabolic MedicineThe Royal Children's HospitalMelbourneAustralia
- Department of Biochemical Genetics, Victorian Clinical Genetics ServiceMurdoch Children's Research InstituteMelbourneAustralia
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15
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The Role of YggS in Vitamin B 6 Homeostasis in Salmonella enterica Is Informed by Heterologous Expression of Yeast SNZ3. J Bacteriol 2020; 202:JB.00383-20. [PMID: 32900833 DOI: 10.1128/jb.00383-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 08/28/2020] [Indexed: 11/20/2022] Open
Abstract
YggS (COG0325) is a pyridoxal 5'-phosphate (PLP)-binding protein proposed to be involved in homeostasis of B6 vitamers. In Salmonella enterica, lack of yggS resulted in phenotypes that were distinct and others that were similar to those of a yggS mutant of Escherichia coli Like other organisms, yggS mutants of S. enterica accumulate endogenous pyridoxine 5'-phosphate (PNP). Data herein show that strains lacking YggS accumulated ∼10-fold more PLP in growth medium than a parental strain. The deoxyxylulose 5-phosphate-dependent biosynthetic pathway for PLP and the PNP/pyridoxamine 5'-phosphate (PMP) oxidase credited with interconverting B6 vitamers were replaced with a single PLP synthase from Saccharomyces cerevisiae The impact of a yggS deletion on the intracellular and extracellular levels of B6 vitamers in this restructured strain supported a role for PdxH in PLP homeostasis and led to a general model for YggS function in PLP-PMP cycling. Our findings uncovered broader consequences of a yggS mutation than previously reported and suggest that the accumulation of PNP is not a direct effect of lacking YggS but rather a downstream consequence.IMPORTANCE Pyridoxal 5'-phosphate (PLP) is an essential cofactor for enzymes in all domains of life. Perturbations in PLP or B6 vitamer content can be detrimental, notably causing B6-dependent epilepsy in humans. YggS homologs are broadly conserved and have been implicated in altered levels of B6 vitamers in multiple organisms. The biochemical activity of YggS, expected to be conserved across domains, is not yet known. Herein, a simplified heterologous pathway minimized metabolic variables and allowed the dissection of this system to generate new metabolic knowledge that will be relevant to understanding YggS.
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16
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Labella JI, Cantos R, Salinas P, Espinosa J, Contreras A. Distinctive Features of PipX, a Unique Signaling Protein of Cyanobacteria. Life (Basel) 2020; 10:life10060079. [PMID: 32481703 PMCID: PMC7344720 DOI: 10.3390/life10060079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 05/23/2020] [Accepted: 05/26/2020] [Indexed: 12/20/2022] Open
Abstract
PipX is a unique cyanobacterial protein identified by its ability to bind to PII and NtcA, two key regulators involved in the integration of signals of the nitrogen/carbon and energy status, with a tremendous impact on nitrogen assimilation and gene expression in cyanobacteria. PipX provides a mechanistic link between PII, the most widely distributed signaling protein, and NtcA, a global transcriptional regulator of cyanobacteria. PII, required for cell survival unless PipX is inactivated or down-regulated, functions by protein–protein interactions with transcriptional regulators, transporters, and enzymes. In addition, PipX appears to be involved in a wider signaling network, supported by the following observations: (i) PII–PipX complexes interact with PlmA, an as yet poorly characterized transcriptional regulator also restricted to cyanobacteria; (ii) the pipX gene is functionally connected with pipY, a gene encoding a universally conserved pyridoxal phosphate binding protein (PLPBP) involved in vitamin B6 and amino acid homeostasis, whose loss-of-function mutations cause B6-dependent epilepsy in humans, and (iii) pipX is part of a relatively robust, six-node synteny network that includes pipY and four additional genes that might also be functionally connected with pipX. In this overview, we propose that the study of the protein–protein interaction and synteny networks involving PipX would contribute to understanding the peculiarities and idiosyncrasy of signaling pathways that are conserved in cyanobacteria.
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17
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Labella JI, Llop A, Contreras A. The default cyanobacterial linked genome: an interactive platform based on cyanobacterial linkage networks to assist functional genomics. FEBS Lett 2020; 594:1661-1674. [PMID: 32233038 DOI: 10.1002/1873-3468.13775] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 02/14/2020] [Accepted: 03/12/2020] [Indexed: 01/01/2023]
Abstract
A database of cyanobacterial linked genomes that can be accessed through an interactive platform (https://dfgm.ua.es/genetica/investigacion/cyanobacterial_genetics/Resources.html) was generated on the bases of conservation of gene neighborhood across 124 cyanobacterial species. It allows flexible generation of gene networks at different threshold values. The default cyanobacterial linked genome, whose global properties are analyzed here, connects most of the cyanobacterial core genes. The potential of the web tool is discussed in relation to other bioinformatics approaches based on guilty-by-association principles, with selected examples of networks illustrating its usefulness for genes found exclusively in cyanobacteria or in cyanobacteria and chloroplasts. We believe that this tool will provide useful predictions that are readily testable in Synechococcus elongatus PCC7942 and other model organisms performing oxygenic photosynthesis.
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Affiliation(s)
- Jose I Labella
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Spain
| | - Antonio Llop
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Spain
| | - Asuncion Contreras
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Spain
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18
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Abstract
The pyridoxal 5'-phosphate-binding protein (PLPBP) is an evolutionarily conserved protein linked to pyridoxal 5'-phosphate-binding. Although mutations in PLPBP were shown to cause vitamin B6-dependent epilepsy, its cellular role and function remain elusive. We here report a detailed biochemical investigation of human PLPBP and its epilepsy-causing mutants by evaluating stability, cofactor binding, and oligomerization. In this context, chemical cross-linking combined with mass spectrometry unraveled an unexpected dimeric assembly of PLPBP. Furthermore, the interaction network of PLPBP was elucidated by chemical cross-linking paired with co-immunoprecipitation. A mass spectrometric analysis in a PLPBP knockout cell line resulted in distinct proteomic changes compared to wild type cells, including upregulation of several cytoskeleton- and cell division-associated proteins. Finally, transfection experiments with vitamin B6-dependent epilepsy-causing PLPBP variants indicate a potential role of PLPBP in cell division as well as proper muscle function. Taken together, our studies on the structure and cellular role of human PLPBP enable a better understanding of the physiological and pathological mechanism of this important protein.
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Affiliation(s)
- Anja Fux
- Department
of Chemistry, Chair of Organic Chemistry II, Center for Integrated
Protein Science (CIPSM), Technische Universität
München, Lichtenbergstraße 4, 85748 Garching, Germany
| | - Stephan A. Sieber
- Department
of Chemistry, Chair of Organic Chemistry II, Center for Integrated
Protein Science (CIPSM), Technische Universität
München, Lichtenbergstraße 4, 85748 Garching, Germany
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19
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Johnstone DL, Al-Shekaili HH, Tarailo-Graovac M, Wolf NI, Ivy AS, Demarest S, Roussel Y, Ciapaite J, van Roermund CWT, Kernohan KD, Kosuta C, Ban K, Ito Y, McBride S, Al-Thihli K, Abdelrahim RA, Koul R, Al Futaisi A, Haaxma CA, Olson H, Sigurdardottir LY, Arnold GL, Gerkes EH, Boon M, Heiner-Fokkema MR, Noble S, Bosma M, Jans J, Koolen DA, Kamsteeg EJ, Drögemöller B, Ross CJ, Majewski J, Cho MT, Begtrup A, Wasserman WW, Bui T, Brimble E, Violante S, Houten SM, Wevers RA, van Faassen M, Kema IP, Lepage N, Lines MA, Dyment DA, Wanders RJA, Verhoeven-Duif N, Ekker M, Boycott KM, Friedman JM, Pena IA, van Karnebeek CDM. PLPHP deficiency: clinical, genetic, biochemical, and mechanistic insights. Brain 2020; 142:542-559. [PMID: 30668673 DOI: 10.1093/brain/awy346] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 10/30/2018] [Accepted: 11/13/2018] [Indexed: 12/20/2022] Open
Abstract
Biallelic pathogenic variants in PLPBP (formerly called PROSC) have recently been shown to cause a novel form of vitamin B6-dependent epilepsy, the pathophysiological basis of which is poorly understood. When left untreated, the disease can progress to status epilepticus and death in infancy. Here we present 12 previously undescribed patients and six novel pathogenic variants in PLPBP. Suspected clinical diagnoses prior to identification of PLPBP variants included mitochondrial encephalopathy (two patients), folinic acid-responsive epilepsy (one patient) and a movement disorder compatible with AADC deficiency (one patient). The encoded protein, PLPHP is believed to be crucial for B6 homeostasis. We modelled the pathogenicity of the variants and developed a clinical severity scoring system. The most severe phenotypes were associated with variants leading to loss of function of PLPBP or significantly affecting protein stability/PLP-binding. To explore the pathophysiology of this disease further, we developed the first zebrafish model of PLPHP deficiency using CRISPR/Cas9. Our model recapitulates the disease, with plpbp-/- larvae showing behavioural, biochemical, and electrophysiological signs of seizure activity by 10 days post-fertilization and early death by 16 days post-fertilization. Treatment with pyridoxine significantly improved the epileptic phenotype and extended lifespan in plpbp-/- animals. Larvae had disruptions in amino acid metabolism as well as GABA and catecholamine biosynthesis, indicating impairment of PLP-dependent enzymatic activities. Using mass spectrometry, we observed significant B6 vitamer level changes in plpbp-/- zebrafish, patient fibroblasts and PLPHP-deficient HEK293 cells. Additional studies in human cells and yeast provide the first empirical evidence that PLPHP is localized in mitochondria and may play a role in mitochondrial metabolism. These models provide new insights into disease mechanisms and can serve as a platform for drug discovery.
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Affiliation(s)
- Devon L Johnstone
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Hilal H Al-Shekaili
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Maja Tarailo-Graovac
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada.,Institute of Physiology and Biochemistry, Faculty of Biology, The University of Belgrade, Belgrade, Serbia.,Departments of Biochemistry, Molecular Biology, and Medical Genetics, Cumming School of Medicine, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Nicole I Wolf
- Department of Child Neurology, Amsterdam University Medical Centres, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Autumn S Ivy
- Division of Child Neurology, Department of Neurology and Neurological Sciences, Stanford University School of Medicine, CA, USA
| | - Scott Demarest
- Departments of Pediatrics and Neurology, University of Colorado School of Medicine, Children's Hospital Colorado, CO, USA
| | - Yann Roussel
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Jolita Ciapaite
- Department of Genetics, Center for Molecular Medicine, University Medical Center, Utrecht, The Netherlands
| | - Carlo W T van Roermund
- Department of Pediatrics and Clinical Chemistry, Laboratory Division, Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Kristin D Kernohan
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Ceres Kosuta
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Kevin Ban
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Yoko Ito
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Skye McBride
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Khalid Al-Thihli
- Genetic and Developmental Medicine Clinic, Sultan Qaboos University Hospital, Muscat, Oman
| | - Rana A Abdelrahim
- Department of Child Health, Sultan Qaboos University Hospital, Muscat, Oman
| | - Roshan Koul
- Paediatric Neurology Unit, Child Health Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Amna Al Futaisi
- Paediatric Neurology Unit, Child Health Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Charlotte A Haaxma
- Department of Pediatric Neurology, Amalia Children's Hospital and Donders Institute of Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
| | - Heather Olson
- Department of Neurology, Division of Epilepsy and Clinical Neurophysiology, Boston Children's Hospital, Boston, MA, USA
| | - Laufey Yr Sigurdardottir
- Department of Neurology, University of Central Florida, Nemours Children's Hospital, Orlando, FL, USA
| | - Georgianne L Arnold
- Department of Pediatrics, University of Pittsburgh Medical Center, Pittsburg, PA, USA
| | - Erica H Gerkes
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - M Boon
- Department of Neurology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - M Rebecca Heiner-Fokkema
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Sandra Noble
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Marjolein Bosma
- Department of Genetics, Center for Molecular Medicine, University Medical Center, Utrecht, The Netherlands
| | - Judith Jans
- Department of Genetics, Center for Molecular Medicine, University Medical Center, Utrecht, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - David A Koolen
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Britt Drögemöller
- British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada.,Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Colin J Ross
- British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada.,Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Jacek Majewski
- McGill University and Genome Quebec Innovation Centre, Montreal, QC, Canada.,Department of Human Genetics, McGill University, Montreal, QC, Canada
| | | | | | - Wyeth W Wasserman
- British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Tuan Bui
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Elise Brimble
- Department of Neurology and Neurological Sciences, Stanford Medicine, Stanford, CA, USA
| | - Sara Violante
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Sander M Houten
- Department of Genetics and Genomic Sciences and Icahn Institute for Genomics and Multiscale Biology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ron A Wevers
- United for Metabolic Diseases, The Netherlands.,Translational Metabolic Laboratory, Department Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Martijn van Faassen
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Ido P Kema
- Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Nathalie Lepage
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | | | - Matthew A Lines
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Division of Metabolics and Newborn Screening, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - David A Dyment
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Medical Genetics, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Ronald J A Wanders
- Department of Pediatrics and Clinical Chemistry, Laboratory Division, Laboratory Genetic Metabolic Diseases, Amsterdam University Medical Centres, Amsterdam, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - Nanda Verhoeven-Duif
- Department of Genetics, Center for Molecular Medicine, University Medical Center, Utrecht, The Netherlands.,United for Metabolic Diseases, The Netherlands
| | - Marc Ekker
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Medical Genetics, Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - Jan M Friedman
- Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Izabella A Pena
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - Clara D M van Karnebeek
- British Columbia Children's Hospital Research Institute, Vancouver, BC, Canada.,United for Metabolic Diseases, The Netherlands.,Departments of Pediatrics and Clinical Genetics, Amsterdam University Medical Centres, Amsterdam, The Netherlands.,Centre for Molecular Medicine and Therapeutics, Department of Pediatrics, University of British Columbia, Vancouver, Canada
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20
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Ito T, Hori R, Hemmi H, Downs DM, Yoshimura T. Inhibition of glycine cleavage system by pyridoxine 5'-phosphate causes synthetic lethality in glyA yggS and serA yggS in Escherichia coli. Mol Microbiol 2019; 113:270-284. [PMID: 31677193 DOI: 10.1111/mmi.14415] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/30/2019] [Indexed: 12/15/2022]
Abstract
The YggS/Ybl036c/PLPBP family includes conserved pyridoxal 5'-phosphate (PLP)-binding proteins that play a critical role in the homeostasis of vitamin B6 and amino acids. Disruption of members of this family causes pleiotropic effects in many organisms by unknown mechanisms. In Escherichia coli, conditional lethality of the yggS and glyA (encoding serine hydroxymethyltransferase) has been described, but the mechanism of lethality was not determined. Strains lacking yggS and serA (3-phosphoglycerate dehydrogenase) were conditionally lethality in the M9-glucose medium supplemented with Gly. Analyses of vitamin B6 pools found the high-levels of pyridoxine 5'-phosphate (PNP) in the two yggS mutants. Growth defects of the double mutants could be eliminated by overexpressing PNP/PMP oxidase (PdxH) to decrease the PNP levels. Further, a serA pdxH strain, which accumulates PNP in the presence of yggS, exhibited similar phenotype to serA yggS mutant. Together these data suggested the inhibition of the glycine cleavage (GCV) system caused the synthetic lethality. Biochemical assays confirmed that PNP disrupts the GCV system by competing with PLP in GcvP protein. Our data are consistent with a model in which PNP-dependent inhibition of the GCV system causes the conditional lethality observed in the glyA yggS or serA yggS mutants.
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Affiliation(s)
- Tomokazu Ito
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi, 464-8601, Japan
| | - Ran Hori
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi, 464-8601, Japan
| | - Hisashi Hemmi
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi, 464-8601, Japan
| | - Diana M Downs
- Department of Microbiology, University of Georgia, Athens, GA, 30602, USA
| | - Tohru Yoshimura
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi, 464-8601, Japan
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21
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Cantos R, Labella JI, Espinosa J, Contreras A. The nitrogen regulator PipX acts in cis to prevent operon polarity. ENVIRONMENTAL MICROBIOLOGY REPORTS 2019; 11:495-507. [PMID: 30126050 DOI: 10.1111/1758-2229.12688] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/10/2018] [Accepted: 08/10/2018] [Indexed: 06/08/2023]
Abstract
Cyanobacteria, phototrophic organisms performing oxygenic photosynthesis, must adapt their metabolic processes to important environmental challenges, like those imposed by the succession of days and nights. Not surprisingly, certain regulatory proteins are found exclusively in this phylum. One of these unique factors, PipX, provides a mechanistic link between signals of carbon/nitrogen and of energy, transduced by the signalling protein PII, and the control of gene expression by the global nitrogen regulator NtcA. Here we report a new regulatory function of PipX: enhancement in cis of pipY expression, a gene encoding a universally conserved protein involved in amino/keto acid and Pyridoxal phosphate homeostasis. In Synechococcus elongatus and many other cyanobacteria these genes are expressed as a bicistronic pipXY operon. Despite being cis-acting, polarity suppression by PipX is nevertheless reminiscent of the function of NusG paralogues typified by RfaH, which are non-essential operon-specific bacterial factors acting in trans to upregulate horizontally-acquired genes. Furthermore, PipX and members of the NusG superfamily share a TLD/KOW structural domain, suggesting regulatory interactions of PipX with the translation machinery. Our results also suggest that the cis-acting function of PipX is a sophisticated regulatory strategy for maintaining appropriate PipX-PipY stoichiometry.
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Affiliation(s)
- Raquel Cantos
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Jose I Labella
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Javier Espinosa
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Asunción Contreras
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
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22
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Conci J, Alvarez-Paggi D, de Oliveira GAP, Pagani TD, Esperante SA, Borkosky SS, Aran M, Alonso LG, Mohana-Borges R, Prat-Gay GD. Conformational Isomerization Involving Conserved Proline Residues Modulates Oligomerization of the NS1 Interferon Response Inhibitor from the Syncytial Respiratory Virus. Biochemistry 2019; 58:2883-2892. [PMID: 31243994 DOI: 10.1021/acs.biochem.8b01288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Interferon response suppression by the respiratory syncytial virus relies on two unique nonstructural proteins, NS1 and NS2, that interact with cellular partners through high-order complexes. We hypothesized that two conserved proline residues, P81 and P67, participate in the conformational change leading to oligomerization. We found that the molecular dynamics of NS1 show a highly mobile C-terminal helix, which becomes rigid upon in silico replacement of P81. A soluble oligomerization pathway into regular spherical structures at low ionic strengths competes with an aggregation pathway at high ionic strengths with an increase in temperature. P81A requires higher temperatures to oligomerize and has a small positive effect on aggregation, while P67A is largely prone to aggregation. Chemical denaturation shows a first transition, involving a high fluorescence and ellipticity change corresponding to both a conformational change and substantial effects on the environment of its single tryptophan, that is strongly destabilized by P67A but stabilized by P81A. The subsequent global cooperative unfolding corresponding to the main β-sheet core is not affected by the proline mutations. Thus, a clear link exists between the effect of P81 and P67 on the stability of the first transition and oligomerization/aggregation. Interestingly, both P67 and P81 are located far away in space and sequence from the C-terminal helix, indicating a marked global structural dynamics. This provides a mechanism for modulating the oligomerization of NS1 by unfolding of a weak helix that exposes hydrophobic surfaces, linked to the participation of NS1 in multiprotein complexes.
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Affiliation(s)
- Julieta Conci
- Protein Structure-Function and Engineering Laboratory , Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435 , 1405 Buenos Aires , Argentina
| | - Damian Alvarez-Paggi
- Protein Structure-Function and Engineering Laboratory , Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435 , 1405 Buenos Aires , Argentina
| | - Guilherme A P de Oliveira
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica Leopoldo de Meis, Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas , Universidade Federal do Rio de Janeiro , 21941-902 Rio de Janeiro , Brazil
| | - Talita D Pagani
- Instituto de Biofísica Carlos Chagas Filho , Universidade Federal do Rio de Janeiro , 21941-902 Rio de Janeiro , Brazil
| | - Sebastian A Esperante
- Protein Structure-Function and Engineering Laboratory , Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435 , 1405 Buenos Aires , Argentina
| | - Silvina S Borkosky
- Protein Structure-Function and Engineering Laboratory , Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435 , 1405 Buenos Aires , Argentina
| | - Martin Aran
- Protein Structure-Function and Engineering Laboratory , Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435 , 1405 Buenos Aires , Argentina
| | - Leonardo G Alonso
- Protein Structure-Function and Engineering Laboratory , Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435 , 1405 Buenos Aires , Argentina
| | - Ronaldo Mohana-Borges
- Instituto de Biofísica Carlos Chagas Filho , Universidade Federal do Rio de Janeiro , 21941-902 Rio de Janeiro , Brazil
| | - Gonzalo de Prat-Gay
- Protein Structure-Function and Engineering Laboratory , Fundación Instituto Leloir and IIBBA-CONICET , Av. Patricias Argentinas 435 , 1405 Buenos Aires , Argentina
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23
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Conserved Pyridoxal 5'-Phosphate-Binding Protein YggS Impacts Amino Acid Metabolism through Pyridoxine 5'-Phosphate in Escherichia coli. Appl Environ Microbiol 2019; 85:AEM.00430-19. [PMID: 30902856 DOI: 10.1128/aem.00430-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 03/15/2019] [Indexed: 12/31/2022] Open
Abstract
Escherichia coli YggS (COG0325) is a member of the highly conserved pyridoxal 5'-phosphate (PLP)-binding protein (PLPBP) family. Recent studies suggested a role for this protein family in the homeostasis of vitamin B6 and amino acids. The deletion or mutation of a member of this protein family causes pleiotropic effects in many organisms and is causative of vitamin B6-dependent epilepsy in humans. To date, little has been known about the mechanism by which lack of YggS results in these diverse phenotypes. In this study, we determined that the pyridoxine (PN) sensitivity observed in yggS-deficient E. coli was caused by the pyridoxine 5'-phosphate (PNP)-dependent overproduction of Val, which is toxic to E. coli The data suggest that the yggS mutation impacts Val accumulation by perturbing the biosynthetic of Thr from homoserine (Hse). Exogenous Hse inhibited the growth of the yggS mutant, caused further accumulation of PNP, and increased the levels of some intermediates in the Thr-Ile-Val metabolic pathways. Blocking the Thr biosynthetic pathway or decreasing the intracellular PNP levels abolished the perturbations of amino acid metabolism caused by the exogenous PN and Hse. Our data showed that a high concentration of intracellular PNP is the root cause of at least some of the pleiotropic phenotypes described for a yggS mutant of E. coli IMPORTANCE Recent studies showed that deletion or mutation of members of the YggS protein family causes pleiotropic effects in many organisms. Little is known about the causes, mechanisms, and consequences of these diverse phenotypes. It was previously shown that yggS mutations in E. coli result in the accumulation of PNP and some metabolites in the Ile/Val biosynthetic pathway. This work revealed that some exogenous stresses increase the aberrant accumulation of PNP in the yggS mutant. In addition, the current report provides evidence indicating that some, but not all, of the phenotypes of the yggS mutant in E. coli are due to the elevated PNP level. These results will contribute to continuing efforts to determine the molecular functions of the members of the YggS protein family.
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24
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Richts B, Rosenberg J, Commichau FM. A Survey of Pyridoxal 5'-Phosphate-Dependent Proteins in the Gram-Positive Model Bacterium Bacillus subtilis. Front Mol Biosci 2019; 6:32. [PMID: 31134210 PMCID: PMC6522883 DOI: 10.3389/fmolb.2019.00032] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 04/18/2019] [Indexed: 11/13/2022] Open
Abstract
The B6 vitamer pyridoxal 5′-phosphate (PLP) is a co-factor for proteins and enzymes that are involved in diverse cellular processes. Therefore, PLP is essential for organisms from all kingdoms of life. Here we provide an overview about the PLP-dependent proteins from the Gram-positive soil bacterium Bacillus subtilis. Since B. subtilis serves as a model system in basic research and as a production host in industry, knowledge about the PLP-dependent proteins could facilitate engineering the bacteria for biotechnological applications. The survey revealed that the majority of the PLP-dependent proteins are involved in metabolic pathways like amino acid biosynthesis and degradation, biosynthesis of antibacterial compounds, utilization of nucleotides as well as in iron and carbon metabolism. Many PLP-dependent proteins participate in de novo synthesis of the co-factors biotin, folate, heme, and NAD+ as well as in cell wall metabolism, tRNA modification, regulation of gene expression, sporulation, and biofilm formation. A surprisingly large group of PLP-dependent proteins (29%) belong to the group of poorly characterized proteins. This review underpins the need to characterize the PLP-dependent proteins of unknown function to fully understand the “PLP-ome” of B. subtilis.
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Affiliation(s)
- Björn Richts
- Department of General Microbiology, University of Goettingen, Göttingen, Germany
| | - Jonathan Rosenberg
- Department of General Microbiology, University of Goettingen, Göttingen, Germany
| | - Fabian M Commichau
- Department of General Microbiology, University of Goettingen, Göttingen, Germany
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25
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Forcada-Nadal A, Llácer JL, Contreras A, Marco-Marín C, Rubio V. The P II-NAGK-PipX-NtcA Regulatory Axis of Cyanobacteria: A Tale of Changing Partners, Allosteric Effectors and Non-covalent Interactions. Front Mol Biosci 2018; 5:91. [PMID: 30483512 PMCID: PMC6243067 DOI: 10.3389/fmolb.2018.00091] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 10/18/2018] [Indexed: 11/13/2022] Open
Abstract
PII, a homotrimeric very ancient and highly widespread (bacteria, archaea, plants) key sensor-transducer protein, conveys signals of abundance or poorness of carbon, energy and usable nitrogen, converting these signals into changes in the activities of channels, enzymes, or of gene expression. PII sensing is mediated by the PII allosteric effectors ATP, ADP (and, in some organisms, AMP), 2-oxoglutarate (2OG; it reflects carbon abundance and nitrogen scarcity) and, in many plants, L-glutamine. Cyanobacteria have been crucial for clarification of the structural bases of PII function and regulation. They are the subject of this review because the information gathered on them provides an overall structure-based view of a PII regulatory network. Studies on these organisms yielded a first structure of a PII complex with an enzyme, (N-acetyl-Lglutamate kinase, NAGK), deciphering how PII can cause enzyme activation, and how it promotes nitrogen stockpiling as arginine in cyanobacteria and plants. They have also revealed the first clear-cut mechanism by which PII can control gene expression. A small adaptor protein, PipX, is sequestered by PII when nitrogen is abundant and is released when is scarce, swapping partner by binding to the 2OG-activated transcriptional regulator NtcA, co-activating it. The structures of PII-NAGK, PII-PipX, PipX alone, of NtcA in inactive and 2OG-activated forms and as NtcA-2OG-PipX complex, explain structurally PII regulatory functions and reveal the changing shapes and interactions of the T-loops of PII depending on the partner and on the allosteric effectors bound to PII. Cyanobacterial studies have also revealed that in the PII-PipX complex PipX binds an additional transcriptional factor, PlmA, thus possibly expanding PipX roles beyond NtcA-dependency. Further exploration of these roles has revealed a functional interaction of PipX with PipY, a pyridoxal-phosphate (PLP) protein involved in PLP homeostasis whose mutations in the human ortholog cause epilepsy. Knowledge of cellular levels of the different components of this PII-PipX regulatory network and of KD values for some of the complexes provides the basic background for gross modeling of the system at high and low nitrogen abundance. The cyanobacterial network can guide searches for analogous components in other organisms, particularly of PipX functional analogs.
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Affiliation(s)
- Alicia Forcada-Nadal
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - José Luis Llácer
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras - Instituto de Salud Carlos III, Valencia, Spain
| | - Asunción Contreras
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain
| | - Clara Marco-Marín
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras - Instituto de Salud Carlos III, Valencia, Spain
| | - Vicente Rubio
- Instituto de Biomedicina de Valencia del Consejo Superior de Investigaciones Científicas, Valencia, Spain.,Group 739, Centro de Investigación Biomédica en Red de Enfermedades Raras - Instituto de Salud Carlos III, Valencia, Spain
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26
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Tremiño L, Forcada-Nadal A, Rubio V. Insight into vitamin B 6 -dependent epilepsy due to PLPBP (previously PROSC) missense mutations. Hum Mutat 2018; 39:1002-1013. [PMID: 29689137 DOI: 10.1002/humu.23540] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 04/03/2018] [Accepted: 04/20/2018] [Indexed: 11/11/2022]
Abstract
Vitamin B6 -dependent genetic epilepsy was recently associated to mutations in PLPBP (previously PROSC), the human version of the widespread COG0325 gene that encodes TIM-barrel-like pyridoxal phosphate (PLP)-containing proteins of unclear function. We produced recombinantly, purified and characterized human PROSC (called now PLPHP) and its six missense mutants reported in epileptic patients. Normal PLPHP is largely a monomer with PLP bound through a Schiff-base linkage. The PLP-targeting antibiotic d-cycloserine decreased the PLP-bound peak as expected for pseudo-first-order reaction. The p.Leu175Pro mutation grossly misfolded PLPHP. Mutations p.Arg241Gln and p.Pro87Leu decreased protein solubility and yield of pure PLPHP, but their pure forms were well folded, similarly to pure p.Pro40Leu, p.Tyr69Cys, and p.Arg205Gln mutants (judged from CD spectra). PLPHP stability was decreased in p.Arg241Gln, p.Pro40Leu, and p.Arg205Gln mutants (thermofluor assays). The p.Arg241Gln and p.Tyr69Cys mutants respectively lacked PLP or had a decreased amount of this cofactor. With p.Tyr69Cys there was extensive protein dimerization due to disulfide bridge formation, and PLP accessibility was decreased (judged from d-cycloserine reaction). A 3-D model of human PLPHP allowed rationalizing the effects of most mutations. Overall, the six missense mutations caused ill effects and five of them impaired folding or decreased stability, suggesting the potential of pharmacochaperone-based therapeutic approaches.
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Affiliation(s)
- Lorena Tremiño
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain
| | | | - Vicente Rubio
- Instituto de Biomedicina de Valencia (IBV-CSIC), Valencia, Spain.,Group 739 of the Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER-ISCIII), Madrid, Spain
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