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Dadi P, Pauling CW, Shrivastava A, Shah DD. Synthesis of versatile neuromodulatory molecules by a gut microbial glutamate decarboxylase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.02.583032. [PMID: 38915512 PMCID: PMC11195143 DOI: 10.1101/2024.03.02.583032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Dysbiosis of the microbiome correlates with many neurological disorders, yet very little is known about the chemistry that controls the production of neuromodulatory molecules by gut microbes. Here, we found that an enzyme glutamate decarboxylase (BfGAD) of a gut microbe Bacteroides fragilis forms multiple neuromodulatory molecules such as γ-aminobutyric acid (GABA), hypotaurine, taurine, homotaurine, and β-alanine. We evolved BfGAD and doubled its taurine productivity. Additionally, we increased its specificity towards the substrate L-glutamate. Here, we provide a chemical strategy via which the BfGAD activity could be fine-tuned. In future, this strategy could be used to modulate the production of neuromodulatory molecules by gut microbes.
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Affiliation(s)
- Pavani Dadi
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ 85281
- School of Life Sciences, Arizona State University, Tempe, AZ 85281
| | - Clint W. Pauling
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ 85281
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306
| | - Abhishek Shrivastava
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ 85281
- School of Life Sciences, Arizona State University, Tempe, AZ 85281
| | - Dhara D. Shah
- Biodesign Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ 85281
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306
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2
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Fan X, Yu L, Shi Z, Li C, Zeng X, Wu Z, Pan D. Characterization of a novel flavored yogurt enriched in γ-aminobutyric acid fermented by Levilactobacillus brevis CGMCC1.5954. J Dairy Sci 2023; 106:852-867. [PMID: 36494222 DOI: 10.3168/jds.2022-22590] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/02/2022] [Indexed: 12/12/2022]
Abstract
This study developed and characterized a γ-aminobutyric acid (GABA)-enriched yogurt fermented by Levilactobacillus brevis CGMCC1.5954. The GABA content in the yogurt was 147.36 mg/100 mL, which was 317.06% higher than that of the control group. Furthermore, there was a significant improvement in the aroma, hardness, adhesion, cohesiveness, and gelatinousness of yogurt. The chromatography and metabolomics analyses further confirmed the high GABA content in yogurt and its nutritional value, and the metabolic pathway for GABA production by L. brevis 54 was identified. A total of 58 volatile flavor compounds were identified using headspace solid-phase microextraction-gas chromatography-mass spectrometry, of which 2-nonanone and 2-heptanone may be responsible for the high odor score of GABA-enriched yogurt. This study developed a nutritious and unique GABA-enriched flavored yogurt, summarized the metabolic pathway of GABA, and provided a flavor fingerprint that could guide the production of specifically flavored yogurts.
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Affiliation(s)
- Xiankang Fan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315832, China
| | - Luyun Yu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315832, China
| | - Zihang Shi
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315832, China
| | - Chunwei Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315832, China
| | - Xiaoqun Zeng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315832, China
| | - Zhen Wu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, Zhejiang 315211, China.
| | - Daodong Pan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, Zhejiang 315211, China; Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315832, China.
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3
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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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4
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Takagi H, Kozuka K, Mimura K, Nakano S, Ito S. Design of a Full-Consensus Glutamate Decarboxylase and Its Application to GABA Biosynthesis. Chembiochem 2021; 23:e202100447. [PMID: 34545992 DOI: 10.1002/cbic.202100447] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/21/2021] [Indexed: 11/06/2022]
Abstract
Glutamate decarboxylase (GAD) catalyses the decarboxylation of L-glutamate to gamma-aminobutyric acid (GABA). Improvement of the enzymatic properties of GAD is important for the low-cost synthesis of GABA. In this study, utilizing sequences of enzymes homologous with GAD from lactic acid bacteria, highly mutated GADs were designed using sequence-based protein design methods. Two mutated GADs, FcGAD and AncGAD, generated by full-consensus design and ancestral sequence reconstruction, had more desirable properties than native GADs. With respect to thermal stability, the half-life of the designed GADs was about 10 °C higher than that of native GAD. The productivity of FcGAD was considerably higher than those of known GADs; more than 250 mg/L of purified enzyme could be produced in the E. coli expression system. In a production test using 26.4 g of l-glutamate and 3.0 g of resting cells, 17.2 g of GABA could be prepared within one hour, without purification, in a one-pot synthesis.
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Affiliation(s)
- Hiroshi Takagi
- Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan.,Numazu Technical Support Center, Industrial Research Institute of Shizuoka Prefecture, Shizuoka, Japan
| | - Kohei Kozuka
- Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
| | - Kenta Mimura
- Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
| | - Shogo Nakano
- Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan.,PREST, Japan Science and Technology Agency, Saitama, Japan
| | - Sohei Ito
- Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
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5
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Yogeswara IBA, Maneerat S, Haltrich D. Glutamate Decarboxylase from Lactic Acid Bacteria-A Key Enzyme in GABA Synthesis. Microorganisms 2020; 8:microorganisms8121923. [PMID: 33287375 PMCID: PMC7761890 DOI: 10.3390/microorganisms8121923] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/26/2020] [Accepted: 11/27/2020] [Indexed: 01/05/2023] Open
Abstract
Glutamate decarboxylase (l-glutamate-1-carboxylase, GAD; EC 4.1.1.15) is a pyridoxal-5’-phosphate-dependent enzyme that catalyzes the irreversible α-decarboxylation of l-glutamic acid to γ-aminobutyric acid (GABA) and CO2. The enzyme is widely distributed in eukaryotes as well as prokaryotes, where it—together with its reaction product GABA—fulfils very different physiological functions. The occurrence of gad genes encoding GAD has been shown for many microorganisms, and GABA-producing lactic acid bacteria (LAB) have been a focus of research during recent years. A wide range of traditional foods produced by fermentation based on LAB offer the potential of providing new functional food products enriched with GABA that may offer certain health-benefits. Different GAD enzymes and genes from several strains of LAB have been isolated and characterized recently. GABA-producing LAB, the biochemical properties of their GAD enzymes, and possible applications are reviewed here.
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Affiliation(s)
- Ida Bagus Agung Yogeswara
- Food Biotechnology Laboratory, Department of Food Science and Technology, University of Natural Resources and Life Sciences BOKU, Muthgasse 18, 1190 Vienna, Austria;
- Nutrition Department, Faculty of Health, Science and Technology, Universitas Dhyana Pura, Dalung Kuta utara 80361, Bali, Indonesia
- Correspondence:
| | - Suppasil Maneerat
- Faculty of Agro-Industry, Prince of Songkla University, Hat Yai 90110, Songkhla, Thailand;
| | - Dietmar Haltrich
- Food Biotechnology Laboratory, Department of Food Science and Technology, University of Natural Resources and Life Sciences BOKU, Muthgasse 18, 1190 Vienna, Austria;
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Enzymatic kinetic resolution of desmethylphosphinothricin indicates that phosphinic group is a bioisostere of carboxyl group. Commun Chem 2020; 3:121. [PMID: 36703359 PMCID: PMC9814759 DOI: 10.1038/s42004-020-00368-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/04/2020] [Indexed: 01/29/2023] Open
Abstract
Escherichia coli glutamate decarboxylase (EcGadB), a pyridoxal 5'-phosphate (PLP)-dependent enzyme, is highly specific for L-glutamate and was demonstrated to be effectively immobilised for the production of γ-aminobutyric acid (GABA), its decarboxylation product. Herein we show that EcGadB quantitatively decarboxylates the L-isomer of D,L-2-amino-4-(hydroxyphosphinyl)butyric acid (D,L-Glu-γ-PH), a phosphinic analogue of glutamate containing C-P-H bonds. This yields 3-aminopropylphosphinic acid (GABA-PH), a known GABAB receptor agonist and provides previously unknown D-Glu-γ-PH, allowing us to demonstrate that L-Glu-γ-PH, but not D-Glu-γ-PH, is responsible for D,L-Glu-γ-PH antibacterial activity. Furthermore, using GABase, a preparation of GABA-transaminase and succinic semialdehyde dehydrogenase, we show that GABA-PH is converted to 3-(hydroxyphosphinyl)propionic acid (Succinate-PH). Hence, PLP-dependent and NADP+-dependent enzymes are herein shown to recognise and metabolise phosphinic compounds, leaving unaffected the P-H bond. We therefore suggest that the phosphinic group is a bioisostere of the carboxyl group and the metabolic transformations of phosphinic compounds may offer a ground for prodrug design.
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7
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Petronikolou N, Ortega MA, Borisova SA, Nair SK, Metcalf WW. Molecular Basis of Bacillus subtilis ATCC 6633 Self-Resistance to the Phosphono-oligopeptide Antibiotic Rhizocticin. ACS Chem Biol 2019; 14:742-750. [PMID: 30830751 DOI: 10.1021/acschembio.9b00030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Rhizocticins are phosphono-oligopeptide antibiotics that contain a toxic C-terminal ( Z) -l -2-amino-5-phosphono-3-pentenoic acid (APPA) moiety. APPA is an irreversible inhibitor of threonine synthase (ThrC), a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the conversion of O-phospho-l-homoserine to l-threonine. ThrCs are essential for the viability of bacteria, plants, and fungi and are a target for antibiotic development, as de novo threonine biosynthetic pathway is not found in humans. Given the ability of APPA to interfere in threonine metabolism, it is unclear how the producing strain B. subtilis ATCC 6633 circumvents APPA toxicity. Notably, in addition to the housekeeping APPA-sensitive ThrC ( BsThrC), B. subtilis encodes a second threonine synthase (RhiB) encoded within the rhizocticin biosynthetic gene cluster. Kinetic and spectroscopic analyses show that PLP-dependent RhiB is an authentic threonine synthase, converting O-phospho-l-homoserine to threonine with a catalytic efficiency comparable to BsThrC. To understand the structural basis of inhibition, we determined the crystal structure of APPA bound to the housekeeping BsThrC, revealing a covalent complex between the inhibitor and PLP. Structure-based sequence analyses reveal structural determinants within the RhiB active site that contribute to rendering this ThrC homologue resistant to APPA. Together, this work establishes the self-resistance mechanism utilized by B. subtilis ATCC 6633 against APPA exemplifying one of many ways by which bacteria can overcome phosphonate toxicity.
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Affiliation(s)
- Nektaria Petronikolou
- Department of Biochemistry, University of Illinois at Urbana−Champaign, Roger Adams Laboratory, 600 S. Mathews Ave., Urbana, Illinois 61801, United States
| | - Manuel A. Ortega
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 W. Gregory Drive, Urbana, Illinois 61801, United States
| | - Svetlana A. Borisova
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 W. Gregory Drive, Urbana, Illinois 61801, United States
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois at Urbana−Champaign, Roger Adams Laboratory, 600 S. Mathews Ave., Urbana, Illinois 61801, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 W. Gregory Drive, Urbana, Illinois 61801, United States
- Center for Biophysics and Computational Biology, University of Illinois at Urbana−Champaign, Roger Adams Laboratory, 600 S. Mathews Ave., Urbana Illinois 61801, United States
| | - William W. Metcalf
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 W. Gregory Drive, Urbana, Illinois 61801, United States
- Department of Microbiology, University of Illinois at Urbana−Champaign, Chemical and Life Sciences Laboratory, 601 S. Goodwin Ave., Urbana, Illinois 61801, United States
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8
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Tavakoli Y, Esmaeili A, Saber H. Increasing thermal stability and catalytic activity of glutamate decarboxylase in E. coli: An in silico study. Comput Biol Chem 2016; 64:74-81. [PMID: 27294557 DOI: 10.1016/j.compbiolchem.2016.05.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 04/12/2016] [Accepted: 05/19/2016] [Indexed: 11/15/2022]
Abstract
Glutamate decarboxylase (GAD) is an enzyme that converts l-glutamate to gamma amino butyric acid (GABA) that is a widely used drug to treat mental disorders like Alzheimer's disease. In this study for the first time point mutation was performed virtually in the active site of the E. coli GAD in order to increase thermal stability and catalytic activity of the enzyme. Energy minimization and addition of water box were performed using GROMACS 5.4.6 package. PoPMuSiC 2.1 web server was used to predict potential spots for point mutation and Modeller software was used to perform point mutation on three dimensional model. Molegro virtual docker software was used for cavity detection and stimulated docking study. Results indicate that performing mutation separately at positions 164, 302, 304, 393, 396, 398 and 410 increase binding affinity to substrate. The enzyme is predicted to be more thermo- stable in all 7 mutants based on ΔΔG value.
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Affiliation(s)
- Yasaman Tavakoli
- Department of Biotechnology, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan, Iran
| | - Abolghasem Esmaeili
- Cell, Molecular and Developmental Biology Division, Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan, Iran.
| | - Hossein Saber
- Department of Biotechnology, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan, Iran
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Sıdır İ, Sıdır YG, Berber H, Demiray F. Emerging ground and excited state dipole moments and external electric field effect on electronic structure. A solvatochromism and theoretical study on 2-((phenylimino)methyl)phenol derivatives. J Mol Liq 2015. [DOI: 10.1016/j.molliq.2015.01.056] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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10
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De Biase D, Pennacchietti E. Glutamate decarboxylase-dependent acid resistance in orally acquired bacteria: function, distribution and biomedical implications of the gadBC operon. Mol Microbiol 2012; 86:770-86. [PMID: 22995042 DOI: 10.1111/mmi.12020] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2012] [Indexed: 02/06/2023]
Abstract
For successful colonization of the mammalian host, orally acquired bacteria must overcome the extreme acidic stress (pH < 2.5) encountered during transit through the host stomach. The glutamate-dependent acid resistance (GDAR) system is by far the most potent acid resistance system in commensal and pathogenic Escherichia coli, Shigella flexneri, Listeria monocytogenes and Lactococcus lactis. GDAR requires the activity of glutamate decarboxylase (GadB), an intracellular PLP-dependent enzyme which performs a proton-consuming decarboxylation reaction, and of the cognate antiporter (GadC), which performs the glutamatein /γ-aminobutyrateout (GABA) electrogenic antiport. Herein we review recent findings on the structural determinants responsible for pH-dependent intracellular activation of E. coli GadB and GadC. A survey of genomes of bacteria (pathogenic and non-pathogenic), having in common the ability to colonize or to transit through the host gut, shows that the gadB and gadC genes frequently lie next or near each other. This gene arrangement is likely to be important to ensure timely co-regulation of the decarboxylase and the antiporter. Besides the involvement in acid resistance, GABA production and release were found to occur at very high levels in lactic acid bacteria originally isolated from traditionally fermented foods, supporting the evidence that GABA-enriched foods possess health-promoting properties.
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Affiliation(s)
- Daniela De Biase
- Istituto Pasteur - Fondazione Cenci Bolognetti, Dipartimento di Scienze e Biotecnologie Medico-Chirurgiche, Sapienza Università di Roma, 04100, Latina, Italy.
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11
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Minkin VI, Tsukanov AV, Dubonosov AD, Bren VA. Tautomeric Schiff bases: Iono-, solvato-, thermo- and photochromism. J Mol Struct 2011. [DOI: 10.1016/j.molstruc.2011.05.029] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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12
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Pennacchietti E, Lammens TM, Capitani G, Franssen MCR, John RA, Bossa F, De Biase D. Mutation of His465 alters the pH-dependent spectroscopic properties of Escherichia coli glutamate decarboxylase and broadens the range of its activity toward more alkaline pH. J Biol Chem 2009; 284:31587-96. [PMID: 19797049 DOI: 10.1074/jbc.m109.049577] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glutamate decarboxylase (GadB) from Escherichia coli is a hexameric, pyridoxal 5'-phosphate-dependent enzyme catalyzing CO(2) release from the alpha-carboxyl group of L-glutamate to yield gamma-aminobutyrate. GadB exhibits an acidic pH optimum and undergoes a spectroscopically detectable and strongly cooperative pH-dependent conformational change involving at least six protons. Crystallographic studies showed that at mildly alkaline pH GadB is inactive because all active sites are locked by the C termini and that the 340 nm absorbance is an aldamine formed by the pyridoxal 5'-phosphate-Lys(276) Schiff base with the distal nitrogen of His(465), the penultimate residue in the GadB sequence. Herein we show that His(465) has a massive influence on the equilibrium between active and inactive forms, the former being favored when this residue is absent. His(465) contributes with n approximately 2.5 to the overall cooperativity of the system. The residual cooperativity (n approximately 3) is associated with the conformational changes still occurring at the N-terminal ends regardless of the mutation. His(465), dispensable for the cooperativity that affects enzyme activity, is essential to include the conformational change of the N termini into the cooperativity of the whole system. In the absence of His(465), a 330-nm absorbing species appears, with fluorescence emission spectra more complex than model compounds and consisting of two maxima at 390 and 510 nm. Because His(465) mutants are active at pH well above 5.7, they appear to be suitable for biotechnological applications.
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Affiliation(s)
- Eugenia Pennacchietti
- Istituto Pasteur, Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche A. Rossi Fanelli, Sapienza Università di Roma, 00185 Roma, Italy
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13
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Bertoldi M, Voltattorni CB. Multiple roles of the active site lysine of Dopa decarboxylase. Arch Biochem Biophys 2009; 488:130-9. [PMID: 19580779 DOI: 10.1016/j.abb.2009.06.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 06/05/2009] [Accepted: 06/30/2009] [Indexed: 10/20/2022]
Abstract
The pyridoxal 5'-phosphate dependent-enzyme Dopa decarboxylase, responsible for the irreversible conversion of l-Dopa to dopamine, is an attractive drug target. The contribution of the pyridoxal-Lys303 to the catalytic mechanisms of decarboxylation and oxidative deamination is analyzed. The K303A variant binds the coenzyme with a 100-fold decreased apparent equilibrium binding affinity with respect to the wild-type enzyme. Unlike the wild-type, K303A in the presence of l-Dopa displays a parallel progress course of formation of both dopamine and 3,4-dihydroxyphenylacetaldehyde (plus ammonia) with a burst followed by a linear phase. Moreover, the finding that the catalytic efficiencies of decarboxylation and of oxidative deamination display a decrease of 1500- and 17-fold, respectively, with respect to the wild-type, is indicative of a different impact of Lys303 mutation on these reactions. Kinetic analyses reveal that Lys303 is involved in external aldimine formation and hydrolysis as well as in product release which affects the rate-determining step of decarboxylation.
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Affiliation(s)
- Mariarita Bertoldi
- Dipartimento di Scienze Morfologico-Biomediche, Sezione di Chimica Biologica, Facoltà di Medicina e Chirurgia, Università di Verona, 37134 Verona, Italy.
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Campioni S, Mossuto MF, Torrassa S, Calloni G, de Laureto PP, Relini A, Fontana A, Chiti F. Conformational properties of the aggregation precursor state of HypF-N. J Mol Biol 2008; 379:554-67. [DOI: 10.1016/j.jmb.2008.04.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 03/28/2008] [Accepted: 04/01/2008] [Indexed: 10/22/2022]
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15
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Cook PD, Thoden JB, Holden HM. The structure of GDP-4-keto-6-deoxy-D-mannose-3-dehydratase: a unique coenzyme B6-dependent enzyme. Protein Sci 2006; 15:2093-106. [PMID: 16943443 PMCID: PMC2242600 DOI: 10.1110/ps.062328306] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
L-colitose is a 3,6-dideoxysugar found in the O-antigens of some Gram-negative bacteria such as Escherichia coli and in marine bacteria such as Pseudoalteromonas tetraodonis. The focus of this investigation, GDP-4-keto-6-deoxy-D-mannose-3-dehydratase, catalyzes the third step in colitose production, which is the removal of the hydroxyl group at C3' of GDP-4-keto-6-deoxymannose. It is an especially intriguing PLP-dependent enzyme in that it acts as both a transaminase and a dehydratase. Here we present the first X-ray structure of this enzyme isolated from E. coli Strain 5a, type O55:H7. The two subunits of the protein form a tight dimer with a buried surface area of approximately 5000 A2. This is a characteristic feature of the aspartate aminotransferase superfamily. Although the PLP-binding pocket is formed primarily by one subunit, there is a loop, delineated by Phe 240 to Glu 253 in the second subunit, that completes the active site architecture. The hydrated form of PLP was observed in one of the enzyme/cofactor complexes described here. Amino acid residues involved in anchoring the cofactor to the protein include Gly 56, Ser 57, Asp 159, Glu 162, and Ser 183 from one subunit and Asn 248 from the second monomer. In the second enzyme/cofactor complex reported, a glutamate ketimine intermediate was found trapped in the active site. Taken together, these two structures, along with previously reported biochemical data, support the role of His 188 as the active site base required for catalysis.
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Affiliation(s)
- Paul D Cook
- Department of Biochemistry, University of Wisconsin-Madison, Wisconsin 53706, USA
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Gut H, Pennacchietti E, John RA, Bossa F, Capitani G, De Biase D, Grütter MG. Escherichia coli acid resistance: pH-sensing, activation by chloride and autoinhibition in GadB. EMBO J 2006; 25:2643-51. [PMID: 16675957 PMCID: PMC1478166 DOI: 10.1038/sj.emboj.7601107] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2005] [Accepted: 03/27/2006] [Indexed: 01/07/2023] Open
Abstract
Escherichia coli and other enterobacteria exploit the H+ -consuming reaction catalysed by glutamate decarboxylase to survive the stomach acidity before reaching the intestine. Here we show that chloride, extremely abundant in gastric secretions, is an allosteric activator producing a 10-fold increase in the decarboxylase activity at pH 5.6. Cooperativity and sensitivity to chloride were lost when the N-terminal 14 residues, involved in the formation of two triple-helix bundles, were deleted by mutagenesis. X-ray structures, obtained in the presence of the substrate analogue acetate, identified halide-binding sites at the base of each N-terminal helix, showed how halide binding is responsible for bundle stability and demonstrated that the interconversion between active and inactive forms of the enzyme is a stepwise process. We also discovered an entirely novel structure of the cofactor pyridoxal 5'-phosphate (aldamine) to be responsible for the reversibly inactivated enzyme. Our results link the entry of chloride ions, via the H+/Cl- exchange activities of ClC-ec1, to the trigger of the acid stress response in the cell when the intracellular proton concentration has not yet reached fatal values.
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Affiliation(s)
- Heinz Gut
- Biochemisches Institut der Universität Zürich, Zürich, Switzerland
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Capitani G, Tramonti A, Bossa F, Grütter MG, De Biase D. The critical structural role of a highly conserved histidine residue in group II amino acid decarboxylases. FEBS Lett 2003; 554:41-4. [PMID: 14596911 DOI: 10.1016/s0014-5793(03)01079-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Glutamate decarboxylase is a pyridoxal 5'-phosphate (PLP)-dependent enzyme, belonging to the subset of PLP-dependent decarboxylases classified as group II. Site-directed mutagenesis of Escherichia coli glutamate decarboxylase, combined with analysis of the crystal structure, shows that a histidine residue buried in the protein core is critical for correct folding. This histidine is strictly conserved in the PF00282 PFAM family, which includes the group II decarboxylases. A similar role is proposed for residue Ser269, also highly conserved in this group of enzymes, as it provides one of the interactions stabilising His241.
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Affiliation(s)
- Guido Capitani
- Biochemisches Institut der Universität Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
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18
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Bertoldi M, Cellini B, D'Aguanno S, Borri Voltattorni C. Lysine 238 is an essential residue for alpha,beta-elimination catalyzed by Treponema denticola cystalysin. J Biol Chem 2003; 278:37336-43. [PMID: 12882978 DOI: 10.1074/jbc.m305967200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Treponema denticola cystalysin is a pyridoxal 5'-phosphate (PLP) enzyme that catalyzes the alpha,beta-elimination of l-cysteine to pyruvate, ammonia, and H2S. Similar to other PLP enzymes, an active site Lys residue (Lys-238) forms an internal Schiff base with PLP. The mechanistic role of this residue has been studied by an analysis of the mutant enzymes in which Lys-238 has been replaced by Ala (K238A) and Arg (K238R). Both apomutants reconstituted with PLP bind noncovalently approximately 50% of the normal complement of the cofactor and have a lower affinity for the coenzyme than that of wild-type. Kinetic analyses of the reactions of K238A and K238R mutants with glycine compared with that of wild-type demonstrate the decrease of the rate of Schiff base formation by 103- and 7.5 x 104-fold, respectively, and, to a lesser extent, a decrease of the rate of Schiff base hydrolysis. Thus, a role of Lys-238 is to facilitate formation of external aldimine by transimination. Kinetic data reveal that the K238A mutant is inactive in the alpha,beta-elimination of l-cysteine and beta-chloro-l-alanine, whereas K238R retains 0.3% of the wild-type activity. These data, together with those derived from a spectral analysis of the reaction of Lys-238 mutants with unproductive substrate analogues, indicate that Lys-238 is an essential catalytic residue, possibly participating as a general base abstracting the Calpha-proton from the substrate and possibly as a general acid protonating the beta-leaving group.
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Affiliation(s)
- Mariarita Bertoldi
- Dipartimento di Scienze Neurologiche e della Visione, Sezione di Chimica Biologica, Facoltà di Medicina e Chirurgia, Università degli Studi di Verona, Strada Le Grazie, 8, 37134 Verona, Italy
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19
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Capitani G, De Biase D, Aurizi C, Gut H, Bossa F, Grütter MG. Crystal structure and functional analysis of Escherichia coli glutamate decarboxylase. EMBO J 2003; 22:4027-37. [PMID: 12912902 PMCID: PMC175793 DOI: 10.1093/emboj/cdg403] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Glutamate decarboxylase is a vitamin B6-dependent enzyme, which catalyses the decarboxylation of glutamate to gamma-aminobutyrate. In Escherichia coli, expression of glutamate decarboxylase (GadB), a 330 kDa hexamer, is induced to maintain the physiological pH under acidic conditions, like those of the passage through the stomach en route to the intestine. GadB, together with the antiporter GadC, constitutes the gad acid resistance system, which confers the ability for bacterial survival for at least 2 h in a strongly acidic environment. GadB undergoes a pH-dependent conformational change and exhibits an activity optimum at low pH. We determined the crystal structures of GadB at acidic and neutral pH. They reveal the molecular details of the conformational change and the structural basis for the acidic pH optimum. We demonstrate that the enzyme is localized exclusively in the cytoplasm at neutral pH, but is recruited to the membrane when the pH falls. We show by structure-based site-directed mutagenesis that the triple helix bundle formed by the N-termini of the protein at acidic pH is the major determinant for this behaviour.
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Affiliation(s)
- Guido Capitani
- Biochemisches Institut der Universität Zürich, Zürich CH-8057, Switzerland.
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