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Sinha N, Eirich J, Finkemeier I, Grimm B. Glutamate 1-semialdehyde aminotransferase is connected to GluTR by GluTR-binding protein and contributes to the rate-limiting step of 5-aminolevulinic acid synthesis. THE PLANT CELL 2022; 34:4623-4640. [PMID: 35972388 PMCID: PMC9614494 DOI: 10.1093/plcell/koac237] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 07/28/2022] [Indexed: 06/01/2023]
Abstract
Tetrapyrroles play fundamental roles in crucial processes including photosynthesis, respiration, and catalysis. In plants, 5-aminolevulinic acid (ALA) is the common precursor of tetrapyrroles. ALA is synthesized from activated glutamate by the enzymes glutamyl-tRNA reductase (GluTR) and glutamate-1-semialdehyde aminotransferase (GSAAT). ALA synthesis is recognized as the rate-limiting step in this pathway. We aimed to explore the contribution of GSAAT to the control of ALA synthesis and the formation of a protein complex with GluTR. In Arabidopsis thaliana, two genes encode GSAAT isoforms: GSA1 and GSA2. A comparison of two GSA knockout mutants with the wild-type revealed the correlation of reduced GSAAT activity and ALA-synthesizing capacity in leaves with lower chlorophyll content. Growth and green pigmentation were more severely impaired in gsa2 than in gsa1, indicating the predominant role of GSAAT2 in ALA synthesis. Interestingly, GluTR accumulated to higher levels in gsa2 than in the wild-type and was mainly associated with the plastid membrane. We propose that the GSAAT content modulates the amount of soluble GluTR available for ALA synthesis. Several different biochemical approaches revealed the GSAAT-GluTR interaction through the assistance of GluTR-binding protein (GBP). A modeled structure of the tripartite protein complex indicated that GBP mediates the stable association of GluTR and GSAAT for adequate ALA synthesis.
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Affiliation(s)
- Neha Sinha
- Institute of Biology/Plant Physiology, Humboldt-University Berlin, 10115 Berlin, Germany
| | - Jürgen Eirich
- Institute for Plant Biology and Biotechnology, Plant Physiology, Westfälische Wilhelms-Universität, 48149 Muenster, Germany
| | - Iris Finkemeier
- Institute for Plant Biology and Biotechnology, Plant Physiology, Westfälische Wilhelms-Universität, 48149 Muenster, Germany
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2
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Tran JU, Brown BL. Structural Basis for Allostery in PLP-dependent Enzymes. Front Mol Biosci 2022; 9:884281. [PMID: 35547395 PMCID: PMC9081730 DOI: 10.3389/fmolb.2022.884281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 03/25/2022] [Indexed: 11/13/2022] Open
Abstract
Pyridoxal 5'-phosphate (PLP)-dependent enzymes are found ubiquitously in nature and are involved in a variety of biological pathways, from natural product synthesis to amino acid and glucose metabolism. The first structure of a PLP-dependent enzyme was reported over 40 years ago, and since that time, there is a steady wealth of structural and functional information revealed for a wide array of these enzymes. A functional mechanism that is gaining more appreciation due to its relevance in drug design is that of protein allostery, where binding of a protein or ligand at a distal site influences the structure, organization, and function at the active site. Here, we present a review of current structure-based mechanisms of allostery for select members of each PLP-dependent enzyme family. Knowledge of these mechanisms may have a larger potential for identifying key similarities and differences among enzyme families that can eventually be exploited for therapeutic development.
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Affiliation(s)
- Jenny U. Tran
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Breann L. Brown
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, United States
- Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN, United States
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3
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Wang Q, Zhu B, Chen C, Yuan Z, Guo J, Yang X, Wang S, Lv Y, Liu Q, Yang B, Sun C, Wang P, Deng X. A Single Nucleotide Substitution of GSAM Gene Causes Massive Accumulation of Glutamate 1-Semialdehyde and Yellow Leaf Phenotype in Rice. RICE (NEW YORK, N.Y.) 2021; 14:50. [PMID: 34089406 PMCID: PMC8179877 DOI: 10.1186/s12284-021-00492-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 05/12/2021] [Indexed: 05/04/2023]
Abstract
BACKGROUND Tetrapyrroles play indispensable roles in various biological processes. In higher plants, glutamate 1-semialdehyde 2,1-aminomutase (GSAM) converts glutamate 1-semialdehyde (GSA) to 5-aminolevulinic acid (ALA), which is the rate-limiting step of tetrapyrrole biosynthesis. Up to now, GSAM genes have been successively identified from many species. Besides, it was found that GSAM could form a dimeric protein with itself by x-ray crystallography. However, no mutant of GSAM has been identified in monocotyledonous plants, and no experiment on interaction of GSAM protein with itself has been reported so far. RESULT We isolated a yellow leaf mutant, ys53, in rice (Oryza sativa). The mutant showed decreased photosynthetic pigment contents, suppressed chloroplast development, and reduced photosynthetic capacity. In consequence, its major agronomic traits were significantly affected. Map-based cloning revealed that the candidate gene was LOC_Os08g41990 encoding GSAM protein. In ys53 mutant, a single nucleotide substitution in this gene caused an amino acid change in the encoded protein, so its ALA-synthesis ability was significantly reduced and GSA was massively accumulated. Complementation assays suggested the mutant phenotype of ys53 could be rescued by introducing wild-type OsGSAM gene, confirming that the point mutation in OsGSAM is the cause of the mutant phenotype. OsGSAM is mainly expressed in green tissues, and its encoded protein is localized to chloroplast. qRT-PCR analysis indicated that the mutation of OsGSAM not only affected the expressions of tetrapyrrole biosynthetic genes, but also influenced those of photosynthetic genes in rice. In addition, the yeast two-hybrid experiment showed that OsGSAM protein could interact with itself, which could largely depend on the two specific regions containing the 81th-160th and the 321th-400th amino acid residues at its N- and C-terminals, respectively. CONCLUSIONS We successfully characterized rice GSAM gene by a yellow leaf mutant and map-based cloning approach. Meanwhile, we verified that OsGSAM protein could interact with itself mainly by means of the two specific regions of amino acid residues at its N- and C-terminals, respectively.
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Affiliation(s)
- Qian Wang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Baiyang Zhu
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Congping Chen
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Zhaodi Yuan
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Jia Guo
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Xiaorong Yang
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - San Wang
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Yan Lv
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Qingsong Liu
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Bin Yang
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Changhui Sun
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China
| | - Pingrong Wang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China.
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China.
| | - Xiaojian Deng
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China.
- Rice Research Institute, Sichuan Agricultural University, Chengdu, 611130, China.
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4
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Vila-Santa A, Islam MA, Ferreira FC, Prather KLJ, Mira NP. Prospecting Biochemical Pathways to Implement Microbe-Based Production of the New-to-Nature Platform Chemical Levulinic Acid. ACS Synth Biol 2021; 10:724-736. [PMID: 33764057 DOI: 10.1021/acssynbio.0c00518] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Levulinic acid is a versatile platform molecule with potential to be used as an intermediate in the synthesis of many value-added products used across different industries, from cosmetics to fuels. Thus far, microbial biosynthetic pathways having levulinic acid as a product or an intermediate are not known, which restrains the development and optimization of a microbe-based process envisaging the sustainable bioproduction of this chemical. One of the doors opened by synthetic biology in the design of microbial systems is the implementation of new-to-nature pathways, that is, the assembly of combinations of enzymes not observed in vivo, where the enzymes can use not only their native substrates but also non-native ones, creating synthetic steps that enable the production of novel compounds. Resorting to a combined approach involving complementary computational tools and extensive manual curation, in this work, we provide a thorough prospect of candidate biosynthetic pathways that can be assembled for the production of levulinic acid in Escherichia coli or Saccharomyces cerevisiae. Out of the hundreds of combinations screened, five pathways were selected as best candidates on the basis of the availability of substrates and of candidate enzymes to catalyze the synthetic steps (that is, those steps that involve conversions not previously described). Genome-scale metabolic modeling was used to assess the performance of these pathways in the two selected hosts and to anticipate possible bottlenecks. Not only does the herein described approach offer a platform for the future implementation of the microbial production of levulinic acid but also it provides an organized research strategy that can be used as a framework for the implementation of other new-to-nature biosynthetic pathways for the production of value-added chemicals, thus fostering the emerging field of synthetic industrial microbiotechnology.
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Affiliation(s)
- Ana Vila-Santa
- Department of Bioengineering and Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - M. Ahsanul Islam
- Department of Chemical Engineering, Loughborough University, Leicestershire, LE11 3TU Loughborough, United Kingdom
| | - Frederico C. Ferreira
- Department of Bioengineering and Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - Kristala L. J. Prather
- Department of Chemical Engineering and Center for Integrative Synthetic Biology (CISB), Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Nuno P. Mira
- Department of Bioengineering and Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
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5
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Harder-Viddal C, Roshko RM, Stetefeld J. Energy flow and intersubunit signalling in GSAM: A non-equilibrium molecular dynamics study. Comput Struct Biotechnol J 2020; 18:1651-1663. [PMID: 32670505 PMCID: PMC7338781 DOI: 10.1016/j.csbj.2020.06.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/14/2020] [Accepted: 06/16/2020] [Indexed: 12/11/2022] Open
Abstract
Non-equilibrium molecular dynamics simulations of vibrational energy flow induced by the imposition of a thermal gradient have been performed on the μ2-dimeric enzyme glutamate-1-semialdehyde aminomutase (GSAM), the key enzyme in the biosynthesis of chlorophyll, in order to identify energy transport pathways and to elucidate their role as potential allosteric communication networks for coordinating functional dynamics, specifically the negative cooperativity observed in the motion of the two active site gating loops. Fully atomistic MD simulations of thermal diffusion were executed with a GROMACS simulation package on a fully solvated GSAM enzyme by heating various active site target ligands (initially, catalytic intermediates and cofactors) to 300K while holding the remainder of the protein and the solvent bath at 10K and monitoring the temperature T(t) of all the enzyme residues as a function of time over a 1ns observation window. Energy is observed to be deposited in a relatively small number of discrete chains of residues most of which contribute to specific structural or biochemical functionality. Thermal linkages between all thermally active chains were established by isolating a specific pair of chains and performing a thermal diffusion simulation on the pair, one held at 300K and the other at 10K, with the rest of the protein frozen in its initial atomic configuration and thus thermally unresponsive. Proceeding in this way, it was possible to map out multiple pathways of vibrational energy flow leading from one of the active sites through a network of contiguous residues, many of which were evolutionarily conserved and linked by hydrogen bonds, into the other active site and ultimately to the other gating loop.
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Affiliation(s)
- C Harder-Viddal
- Department of Chemistry and Physics, Canadian Mennonite University, 500 Shaftesbury Blvd, Winnipeg, Manitoba, Canada
| | - R M Roshko
- Department of Physics and Astronomy, University of Manitoba, 30A Sifton Rd, Winnipeg, Manitoba, Canada
| | - J Stetefeld
- Department of Chemistry, University of Manitoba, 144 Dysart Rd, Winnipeg, Manitoba, Canada.,Center for Oil and Gas Research and Development (COGRAD), Canada.,Department of Biochemistry and Medical Genetics, University of Manitoba, Canada.,Department of Human Anatomy and Cell Science, University of Manitoba, Canada
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6
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Stojanovski BM, Hunter GA, Na I, Uversky VN, Jiang RHY, Ferreira GC. 5-Aminolevulinate synthase catalysis: The catcher in heme biosynthesis. Mol Genet Metab 2019; 128:178-189. [PMID: 31345668 PMCID: PMC6908770 DOI: 10.1016/j.ymgme.2019.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/27/2019] [Accepted: 06/07/2019] [Indexed: 01/26/2023]
Abstract
5-Aminolevulinate (ALA) synthase (ALAS), a homodimeric pyridoxal-5'-phosphate (PLP)-dependent enzyme, catalyzes the first step of heme biosynthesis in metazoa, fungi and α-proteobacteria. In this review, we focus on the advances made in unraveling the mechanism of the ALAS-catalyzed reaction during the past decade. The interplay between the PLP cofactor and the protein moiety determines and modulates the multi-intermediate reaction cycle of ALAS, which involves the decarboxylative condensation of two substrates, glycine and succinyl-CoA. Substrate binding and catalysis are rapid, and product (ALA) release dominates the overall ALAS kinetic mechanism. Interconversion between a catalytically incompetent, open conformation and a catalytically competent, closed conformation is linked to ALAS catalysis. Reversion to the open conformation, coincident with ALA dissociation, defines the slowest step of the reaction cycle. These findings were further substantiated by introducing seven mutations in the16-amino acid loop that gates the active site, yielding an ALAS variant with a greatly increased rate of catalytic turnover and heightened specificity constants for both substrates. Recently, molecular dynamics (MD) simulation analysis of various dimeric ALAS forms revealed that the seven active site loop mutations caused the proteins to adopt different conformations. In particular, the emergence of a β-strand in the mutated loop, which interacted with two preexisting β-strands to form an anti-parallel three-stranded β-sheet, conferred the murine heptavariant with a more stable open conformation and prompted faster product release than wild-type mALAS2. Moreover, the dynamics of the mALAS2 active site loop anti-correlated with that of the 35 amino acid C-terminal sequence. This led us to propose that this C-terminal extension, which is absent in prokaryotic ALASs, finely tunes mammalian ALAS activity. Based on the above results, we extend our previous proposal to include that discovery of a ligand inducing the mammalian C-terminal extension to fold offers a good prospect for the development of a new drug for X-linked protoporphyria and/or other porphyrias associated with enhanced ALAS activity and/or porphyrin accumulation.
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Affiliation(s)
- Bosko M Stojanovski
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
| | - Gregory A Hunter
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Insung Na
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
| | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia
| | - Rays H Y Jiang
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Gloria C Ferreira
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA; Department of Chemistry, College of Arts and Sciences, University of South Florida, Tampa, FL 33612, USA.
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7
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Kwon S, Lee JH, Kim CM, Ha HJ, Lee SH, Lee CS, Jeon JH, So I, Park HH. Structural insights into the enzyme specificity of a novel ω-transaminase from the thermophilic bacterium Sphaerobacter thermophilus. J Struct Biol 2019; 208:107395. [PMID: 31560999 DOI: 10.1016/j.jsb.2019.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 09/22/2019] [Accepted: 09/24/2019] [Indexed: 10/26/2022]
Abstract
Transaminases are pyridoxal 5'-phosphate-dependent enzymes that reversibly catalyze transamination reactions from an amino group donor substrate to an amino group acceptor substrate. ω-Transaminases (ωTAs) utilize compounds with an amino group not at α-carbon position as their amino group donor substrates. Recently, a novel ωTA with broad substrate specificity and high thermostability from the thermophilic bacterium Sphaerobacter thermophilus (St-ωTA) has been reported. Although St-ωTA has been biochemically characterized, little is known about its determinants of substrate specificity. In the present study, we determined the crystal structure of St-ωTA at 1.9 Å resolution to clarify in detail its mechanism of substrate recognition. The structure of St-ωTA revealed that it has a voluminous active site resulting from the unique spatial arrangement of residues comprising its active site. In addition, our molecular docking simulation results suggest that substrate compounds may bind to active site residues via electrostatic interactions or hydrophobic interactions that can be induced by subtle rearrangements of active site residues. On the basis of these structural analyses, we propose a plausible working model of the enzymatic mechanism of St-ωTA. Our results provide profound structural insights into the substrate specificity of St-ωTA and extend the boundaries of knowledge of TAs.
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Affiliation(s)
- Sunghark Kwon
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Jun Hyuck Lee
- Unit of Research for Practical Application, Korea Polar Research Institute, Incheon 21990, Republic of Korea
| | - Chang Min Kim
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Hyun Ji Ha
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Sung Hoon Lee
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Chang Sup Lee
- College of Pharmacy and Research Institute of Pharmaceutical Science, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Ju-Hong Jeon
- Department of Physiology and Biomedical Sciences, Institute of Human-Environment Interface Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Insuk So
- Department of Physiology and Biomedical Sciences, Institute of Human-Environment Interface Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Hyun Ho Park
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.
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8
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Nardella C, Boi D, di Salvo ML, Barile A, Stetefeld J, Tramonti A, Contestabile R. Isolation of a Complex Formed Between Acinetobacter baumannii HemA and HemL, Key Enzymes of Tetrapyrroles Biosynthesis. Front Mol Biosci 2019; 6:6. [PMID: 30863751 PMCID: PMC6399207 DOI: 10.3389/fmolb.2019.00006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 02/06/2019] [Indexed: 01/19/2023] Open
Abstract
Plants, algae and most bacteria synthesize 5-aminolevulinic acid (ALA), the universal precursor of tetrapyrroles such as heme, chlorophyll and coenzyme B12, by a two-step transformation involving the NADPH-dependent glutamyl-tRNA reductase (HemA), which reduces tRNA-bound glutamate to glutamate-1-semialdehyde (GSA), and the pyridoxamine 5′-phosphate-dependent glutamate-1-semialdehyde-2,1-aminomutase (HemL), responsible for the isomerization of GSA into ALA. Since GSA is a very unstable compound at pH values around neutrality, the formation of a HemA-HemL complex has been proposed to occur, allowing for direct channeling of this intermediate from HemA to HemL. Experimental evidence of the formation of this complex has been obtained with the enzymes from Escherichia coli and Chlamydomonas reinhardtii. However, its isolation has never been attained, probably because HemA is degraded when intracellular heme accumulates. In this work, we devised a co-expression and co-purification strategy of HemA and HemL from Acinetobacter baumannii, which allowed the isolation of the HemA-HemL complex. Our results indicate that HemA is stabilized when co-expressed with HemL. The addition of citrate throughout the expression and purification procedure further promotes the formation of the HemA-HemL complex, which can be isolated in fair amount for functional and structural studies. This work lays the bases for a rational design of HemA-HemA inhibitors to be developed as antibacterial agents against A. baumannii, a multidrug resistant opportunistic pathogen responsible for a broad range of severe nosocomial infections.
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Affiliation(s)
- Caterina Nardella
- Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy
| | - Dalila Boi
- Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy
| | - Martino L di Salvo
- Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy
| | - Anna Barile
- Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy
| | - Jörg Stetefeld
- Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada
| | - Angela Tramonti
- Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy.,Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Rome, Italy
| | - Roberto Contestabile
- Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche "A. Rossi Fanelli", Sapienza Università di Roma, Rome, Italy
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9
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Isupov MN, Boyko KM, Sutter JM, James P, Sayer C, Schmidt M, Schönheit P, Nikolaeva AY, Stekhanova TN, Mardanov AV, Ravin NV, Bezsudnova EY, Popov VO, Littlechild JA. Thermostable Branched-Chain Amino Acid Transaminases From the Archaea Geoglobus acetivorans and Archaeoglobus fulgidus: Biochemical and Structural Characterization. Front Bioeng Biotechnol 2019; 7:7. [PMID: 30733943 PMCID: PMC6353796 DOI: 10.3389/fbioe.2019.00007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/08/2019] [Indexed: 11/25/2022] Open
Abstract
Two new thermophilic branched chain amino acid transaminases have been identified within the genomes of different hyper-thermophilic archaea, Geoglobus acetivorans, and Archaeoglobus fulgidus. These enzymes belong to the class IV of transaminases as defined by their structural fold. The enzymes have been cloned and over-expressed in Escherichia coli and the recombinant enzymes have been characterized both biochemically and structurally. Both enzymes showed high thermostability with optimal temperature for activity at 80 and 85°C, respectively. They retain good activity after exposure to 50% of the organic solvents, ethanol, methanol, DMSO and acetonitrile. The enzymes show a low activity to (R)-methylbenzylamine but no activity to (S)-methylbenzylamine. Both enzymes have been crystallized and their structures solved in the internal aldimine form, to 1.9 Å resolution for the Geoglobus enzyme and 2.0 Å for the Archaeoglobus enzyme. Also the Geoglobus enzyme structure has been determined in complex with the amino acceptor α-ketoglutarate and the Archaeoglobus enzyme in complex with the inhibitor gabaculine. These two complexes have helped to determine the conformation of the enzymes during enzymatic turnover and have increased understanding of their substrate specificity. A comparison has been made with another (R) selective class IV transaminase from the fungus Nectria haematococca which was previously studied in complex with gabaculine. The subtle structural differences between these enzymes has provided insight regarding their different substrate specificities.
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Affiliation(s)
- Michail N. Isupov
- Henry Wellcome Building for Biocatalysis, Biosciences, University of Exeter, Exeter, United Kingdom
| | - Konstantin M. Boyko
- Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Jan-Moritz Sutter
- Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Kiel, Germany
| | - Paul James
- Henry Wellcome Building for Biocatalysis, Biosciences, University of Exeter, Exeter, United Kingdom
| | - Christopher Sayer
- Henry Wellcome Building for Biocatalysis, Biosciences, University of Exeter, Exeter, United Kingdom
| | - Marcel Schmidt
- Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Kiel, Germany
| | - Peter Schönheit
- Institut für Allgemeine Mikrobiologie, Christian-Albrechts-Universität Kiel, Kiel, Germany
| | - Alena Yu. Nikolaeva
- Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | | | - Andrey V. Mardanov
- Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Nikolai V. Ravin
- Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | | | - Vladimir O. Popov
- Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Jennifer A. Littlechild
- Henry Wellcome Building for Biocatalysis, Biosciences, University of Exeter, Exeter, United Kingdom
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10
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Walton CJW, Thiebaut F, Brunzelle JS, Couture JF, Chica RA. Structural Determinants of the Stereoinverting Activity of Pseudomonas stutzeri d-Phenylglycine Aminotransferase. Biochemistry 2018; 57:5437-5446. [PMID: 30153007 DOI: 10.1021/acs.biochem.8b00767] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aromatic d-amino acids are key precursors for the production of many small molecule therapeutics. Therefore, the development of biocatalytic methods for their synthesis is of great interest. An enzyme that has great potential as a biocatalyst for the synthesis of d-amino acids is the stereoinverting d-phenylglycine aminotransferase (DPAT) from Pseudomonas stutzeri ST-201. This enzyme catalyzes a unique l to d transamination reaction that produces d-phenylglycine and α-ketoglutarate from benzoylformate and l-glutamate, via a mechanism that is poorly understood. Here, we present the crystal structure of DPAT, which shows that the enzyme folds into a two-domain structure representative of class III aminotransferases. Guided by the crystal structure, we performed saturation mutagenesis to probe the substrate binding pockets of the enzyme. These experiments helped us identify two arginine residues (R34 and R407), one in each binding pocket, that are essential to catalysis. Together with kinetic analyses using a library of amino acid substrates, our mutagenesis and structural studies allow us to propose a binding model that explains the dual l/d specificity of DPAT. Our kinetic analyses also demonstrate that DPAT can catalyze the transamination of β- and γ-amino acids, reclassifying this enzyme as an ω-aminotransferase. Collectively, our studies highlight that the DPAT active site is amenable to protein engineering for expansion of its substrate scope, which offers the opportunity to generate new biocatalysts for the synthesis of a variety of valuable optically pure d-amino acids from inexpensive and abundant l-amino acids.
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Affiliation(s)
- Curtis J W Walton
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa , Ontario , Canada K1N 6N5.,Centre for Catalysis Research and Innovation , University of Ottawa , Ottawa , Ontario , Canada K1N 6N5
| | - Frédéric Thiebaut
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa , Ontario , Canada K1N 6N5.,Centre for Catalysis Research and Innovation , University of Ottawa , Ottawa , Ontario , Canada K1N 6N5
| | - Joseph S Brunzelle
- Life Science Collaborative Access Team, Northwestern Synchrotron Research Centers , Northwestern University , Argonne , Illinois 60439 , United States
| | - Jean-François Couture
- Centre for Catalysis Research and Innovation , University of Ottawa , Ottawa , Ontario , Canada K1N 6N5.,Department of Biochemistry, Microbiology and Immunology, and Ottawa Institute of Systems Biology , University of Ottawa , Ottawa , Ontario , Canada K1H 8M5
| | - Roberto A Chica
- Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa , Ontario , Canada K1N 6N5.,Centre for Catalysis Research and Innovation , University of Ottawa , Ottawa , Ontario , Canada K1N 6N5
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11
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Li S, Lou X, Xu Y, Teng X, Che S, Liu R, Bartlam M. Crystal structure of a glutamate-1-semialdehyde-aminomutase from Pseudomonas aeruginosa PAO1. Biochem Biophys Res Commun 2018; 500:804-809. [DOI: 10.1016/j.bbrc.2018.04.163] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 04/19/2018] [Indexed: 11/29/2022]
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12
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Ouyang M, Li X, Zhao S, Pu H, Shen J, Adam Z, Clausen T, Zhang L. The crystal structure of Deg9 reveals a novel octameric-type HtrA protease. NATURE PLANTS 2017; 3:973-982. [PMID: 29180814 DOI: 10.1038/s41477-017-0060-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 10/23/2017] [Indexed: 05/25/2023]
Abstract
The high temperature requirement A (HtrA) proteases (also termed Deg proteases) play important roles in diverse organisms by regulating protein quality and quantity. One of the 16 Arabidopsis homologs, Deg9, is located in the nucleus where it modulates cytokinin- and light-mediated signalling via degrading the ARABIDOPSIS RESPONSE REGULATOR 4 (ARR4). To uncover the structural features underlying the proteolytic activity of Deg9, we determined its crystal structure. Unlike the well-established trimeric building block of HtrAs, Deg9 displays a novel octameric structure consisting of two tetrameric rings that have distinct conformations. Based on the structural architecture, we generated several mutant variants of Deg9, determined their structure and tested their proteolytic activity towards ARR4. The results of the structural and biochemical analyses allowed us to propose a model for a novel mechanism of substrate recognition and activity regulation of Deg9. In this model, protease activation of one tetramer is mediated by en-bloc reorientation of the protease domains to open an entrance for the substrate in the opposite (inactive) tetramer. This study provides the structural basis for understanding how the levels of nuclear signal components are regulated by a plant protease.
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Affiliation(s)
- Min Ouyang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Xiaoyi Li
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Shun Zhao
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Hua Pu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Jianren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- Research Institute for Interdisciplinary Science and Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Zach Adam
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Tim Clausen
- Research Institute of Molecular Pathology (IMP), Vienna, Austria
| | - Lixin Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.
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13
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Na I, DeForte S, Stojanovski BM, Ferreira GC, Uversky VN. Molecular dynamics analysis of the structural and dynamic properties of the functionally enhanced hepta-variant of mouse 5-aminolevulinate synthase. J Biomol Struct Dyn 2017; 36:152-165. [PMID: 27928941 DOI: 10.1080/07391102.2016.1269688] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Heme biosynthesis, a complex, multistage, and tightly controlled process, starts with 5-aminolevulinate (ALA) production, which, in metazoa and certain bacteria, is a reaction catalyzed by 5-aminolevulinate synthase (ALAS), a pyridoxal 5'-phosphate (PLP)-dependent enzyme. Functional aberrations in ALAS are associated with several human diseases. ALAS can adopt open and closed conformations, with segmental rearrangements of a C-terminal, 16-amino acid loop and an α-helix regulating accessibility to the ALAS active site. Of the murine erythroid ALAS (mALAS2) forms previously engineered to assess the role of the flexible C-terminal loop versus mALAS2 function one stood out due to its impressive gain in catalytic power. To elucidate how the simultaneously introduced seven mutations of this activity-enhanced variant affected structural and dynamic properties of mALAS2, we conducted extensive molecular dynamics simulation analysis of the dimeric forms of wild-type mALAS2, hepta-variant and Rhodobacter capsulatus ALAS (aka R. capsulatus HemA). This analysis revealed that the seven simultaneous mutations in the C-terminal loop, which extends over the active site of the enzyme, caused the bacterial and murine proteins to adopt different conformations. Specifically, a new β-strand in the mutated 'loop' led to interaction with two preexisting β-strands and formation of an anti-parallel three-stranded β-sheet, which likely endowed the murine hepta-variant a more 'stable' open conformation than that of wild-type mALAS2, consistent with a kinetic mechanism involving a faster closed-to-open conformation transition and product release for the mutated than wild-type enzyme. Further, the dynamic behavior of the mALAS2 protomers was strikingly different in the two dimeric forms.
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Affiliation(s)
- Insung Na
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA
| | - Shelly DeForte
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA
| | - Bosko M Stojanovski
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA
| | - Gloria C Ferreira
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA.,b Department of Chemistry , College of Arts and Sciences, University of South Florida , Tampa , FL 33612 , USA
| | - Vladimir N Uversky
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA.,c USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine , University of South Florida , Tampa , Florida 33612 , USA.,d Laboratory of Structural Dynamics, Stability and Folding of Proteins , Institute of Cytology, Russian Academy of Sciences , St. Petersburg , Russia
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14
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Song Y, Pu H, Jiang T, Zhang L, Ouyang M. Crystal structure of glutamate-1-semialdehyde-2,1-aminomutase from Arabidopsis thaliana. Acta Crystallogr F Struct Biol Commun 2016; 72:448-56. [PMID: 27303897 PMCID: PMC4909244 DOI: 10.1107/s2053230x16007263] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/30/2016] [Indexed: 11/19/2022] Open
Abstract
Glutamate-1-semialdehyde-2,1-aminomutase (GSAM) catalyzes the isomerization of glutamate-1-semialdehyde (GSA) to 5-aminolevulinate (ALA) and is distributed in archaea, most bacteria and plants. Although structures of GSAM from archaea and bacteria have been resolved, a GSAM structure from a higher plant is not available, preventing further structure-function analysis. Here, the structure of GSAM from Arabidopsis thaliana (AtGSA1) obtained by X-ray crystallography is reported at 1.25 Å resolution. AtGSA1 forms an asymmetric dimer and displays asymmetry in cofactor binding as well as in the gating-loop orientation, which is consistent with previously reported Synechococcus GSAM structures. While one monomer binds PMP with the gating loop fixed in the open state, the other monomer binds either PMP or PLP and the gating loop is ready to close. The data also reveal the mobility of residues Gly163, Ser164 and Gly165, which are important for reorientation of the gating loop. Furthermore, the asymmetry of the AtGSA1 structure supports the previously proposed negative cooperativity between monomers of GSAM.
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Affiliation(s)
- Yingxian Song
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People’s Republic of China
| | - Hua Pu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People’s Republic of China
| | - Tian Jiang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People’s Republic of China
| | - Lixin Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People’s Republic of China
| | - Min Ouyang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People’s Republic of China
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15
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The Arabidopsis glutamyl-tRNA reductase (GluTR) forms a ternary complex with FLU and GluTR-binding protein. Sci Rep 2016; 6:19756. [PMID: 26794057 PMCID: PMC4726326 DOI: 10.1038/srep19756] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 12/17/2015] [Indexed: 11/09/2022] Open
Abstract
Tetrapyrrole biosynthesis is an essential and tightly regulated process, and glutamyl-tRNA reductase (GluTR) is a key target for multiple regulatory factors at the post-translational level. By binding to the thylakoid membrane protein FLUORESCENT (FLU) or the soluble stromal GluTR-binding protein (GBP), the activity of GluTR is down- or up-regulated. Here, we reconstructed a ternary complex composed of the C-terminal tetratricopepetide-repeat domain of FLU, GBP, and GluTR, crystallized and solved the structure of the complex at 3.2 Å. The overall structure resembles the shape of merged two binary complexes as previously reported, and shows a large conformational change within GluTR. We also demonstrated that GluTR binds tightly with GBP but does not bind to GSAM under the same condition. These findings allow us to suggest a biological role of the ternary complex for the regulation of plant GluTR.
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16
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Schiroli D, Peracchi A. A subfamily of PLP-dependent enzymes specialized in handling terminal amines. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1200-11. [PMID: 25770684 DOI: 10.1016/j.bbapap.2015.02.023] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/23/2015] [Accepted: 02/26/2015] [Indexed: 01/04/2023]
Abstract
The present review focuses on a subfamily of pyridoxal phosphate (PLP)-dependent enzymes, belonging to the broader fold-type I structural group and whose archetypes can be considered ornithine δ-transaminase and γ-aminobutyrate transaminase. These proteins were originally christened "subgroup-II aminotransferases" (AT-II) but are very often referred to as "class-III aminotransferases". As names suggest, the subgroup includes mainly transaminases, with just a few interesting exceptions. However, at variance with most other PLP-dependent enzymes, catalysts in this subfamily seem specialized at utilizing substrates whose amino function is not adjacent to a carboxylate group. AT-II enzymes are widespread in biology and play mostly catabolic roles. Furthermore, today several transaminases in this group are being used as bioorganic tools for the asymmetric synthesis of chiral amines. We present an overview of the biochemical and structural features of these enzymes, illustrating how they are distinctive and how they compare with those of the other fold-type I enzymes. This article is part of a Special Issue entitled: Cofactor-dependent proteins: evolution, chemical diversity and bio-applications.
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Affiliation(s)
- Davide Schiroli
- Department of Life Sciences, Laboratory of Biochemistry, Molecular Biology and Bioinformatics, University of Parma, 43124 Parma, Italy
| | - Alessio Peracchi
- Department of Life Sciences, Laboratory of Biochemistry, Molecular Biology and Bioinformatics, University of Parma, 43124 Parma, Italy.
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17
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Steffen-Munsberg F, Vickers C, Kohls H, Land H, Mallin H, Nobili A, Skalden L, van den Bergh T, Joosten HJ, Berglund P, Höhne M, Bornscheuer UT. Bioinformatic analysis of a PLP-dependent enzyme superfamily suitable for biocatalytic applications. Biotechnol Adv 2015; 33:566-604. [PMID: 25575689 DOI: 10.1016/j.biotechadv.2014.12.012] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 12/16/2014] [Accepted: 12/17/2014] [Indexed: 01/25/2023]
Abstract
In this review we analyse structure/sequence-function relationships for the superfamily of PLP-dependent enzymes with special emphasis on class III transaminases. Amine transaminases are highly important for applications in biocatalysis in the synthesis of chiral amines. In addition, other enzyme activities such as racemases or decarboxylases are also discussed. The substrate scope and the ability to accept chemically different types of substrates are shown to be reflected in conserved patterns of amino acids around the active site. These findings are condensed in a sequence-function matrix, which facilitates annotation and identification of biocatalytically relevant enzymes and protein engineering thereof.
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Affiliation(s)
- Fabian Steffen-Munsberg
- Dept. of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, Greifswald University, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany; KTH Royal Institute of Technology, School of Biotechnology, Division of Industrial Biotechnology, AlbaNova University Center, SE-106 91 Stockholm, Sweden
| | - Clare Vickers
- Dept. of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, Greifswald University, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Hannes Kohls
- Dept. of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, Greifswald University, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany; Protein Biochemistry, Institute of Biochemistry, Greifswald University, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Henrik Land
- KTH Royal Institute of Technology, School of Biotechnology, Division of Industrial Biotechnology, AlbaNova University Center, SE-106 91 Stockholm, Sweden
| | - Hendrik Mallin
- Dept. of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, Greifswald University, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Alberto Nobili
- Dept. of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, Greifswald University, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Lilly Skalden
- Dept. of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, Greifswald University, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Tom van den Bergh
- Bio-Prodict, Nieuwe Marktstraat 54E, 6511 AA Nijmegen, The Netherlands
| | - Henk-Jan Joosten
- Bio-Prodict, Nieuwe Marktstraat 54E, 6511 AA Nijmegen, The Netherlands
| | - Per Berglund
- KTH Royal Institute of Technology, School of Biotechnology, Division of Industrial Biotechnology, AlbaNova University Center, SE-106 91 Stockholm, Sweden
| | - Matthias Höhne
- Protein Biochemistry, Institute of Biochemistry, Greifswald University, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany.
| | - Uwe T Bornscheuer
- Dept. of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, Greifswald University, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany.
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18
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Crystal structure of Arabidopsis glutamyl-tRNA reductase in complex with its stimulator protein. Proc Natl Acad Sci U S A 2014; 111:6630-5. [PMID: 24753615 DOI: 10.1073/pnas.1400166111] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tetrapyrrole biosynthesis in plants, algae, and most bacteria starts from the NADPH-dependent reduction of glutamyl-tRNA by glutamyl-tRNA reductase (GluTR). The GluTR-catalyzed reaction is the rate-limiting step, and GluTR is the target of multiple posttranslational regulations, such as heme feedback inhibition, for the tetrapyrrole biosynthetic pathway. A recently identified GluTR regulator, GluTR binding protein (GluBP), has been shown to spatially organize tetrapyrrole synthesis by distributing GluTR into different suborganellar locations. Here we report the complex structure of GluTR-GluBP from Arabidopsis thaliana. The dimeric GluBP binds symmetrically to the catalytic domains of the V-shaped GluTR dimer via its C-terminal domain. A substantial conformational change of the GluTR NADPH-binding domain is observed, confirming the postulated rotation of the NADPH-binding domain for hydride transfer from NADPH to the substrate. Arg146, "guarding the door" for metabolic channeling, adopts alternative conformations, which may represent steps involved in substrate recognition and product release. A coupled enzyme assay shows that GluBP stimulates GluTR catalytic efficiency with an approximate threefold increase of the 5-aminolevulinic acid formation rate. In addition, the GluTR activity can be inhibited by heme in a concentration-dependent way regardless of the presence of GluBP. A structural alignment indicates that GluBP belongs to a heme-binding family involved in heme metabolism. We propose a catalytic mechanism model for GluTR, through which photosynthetic organisms can achieve precise regulation of tetrapyrrole biosynthesis.
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Asymmetry of the active site loop conformation between subunits of glutamate-1-semialdehyde aminomutase in solution. BIOMED RESEARCH INTERNATIONAL 2013; 2013:353270. [PMID: 23984351 PMCID: PMC3747428 DOI: 10.1155/2013/353270] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 06/27/2013] [Indexed: 02/02/2023]
Abstract
Glutamate-1-semialdehyde aminomutase (GSAM) is a dimeric, pyridoxal 5′-phosphate (PLP)- dependent enzyme catalysing in plants and some bacteria the isomerization of L-glutamate-1-semialdehyde to 5-aminolevulinate, a common precursor of chlorophyll, haem, coenzyme B12, and other tetrapyrrolic compounds. During the catalytic cycle, the coenzyme undergoes conversion from pyridoxamine 5′-phosphate (PMP) to PLP. The entrance of the catalytic site is protected by a loop that is believed to switch from an open to a closed conformation during catalysis. Crystallographic studies indicated that the structure of the mobile loop is related to the form of the cofactor bound to the active site, allowing for asymmetry within the dimer. Since no information on structural and functional asymmetry of the enzyme in solution is available in the literature, we investigated the active site accessibility by determining the cofactor fluorescence quenching of PMP- and PLP-GSAM forms. PLP-GSAM is partially quenched by potassium iodide, suggesting that at least one catalytic site is accessible to the anionic quencher and therefore confirming the asymmetry observed in the crystal structure. Iodide induces release of the cofactor from PMP-GSAM, apparently from only one catalytic site, therefore suggesting an asymmetry also in this form of the enzyme in solution, in contrast with the crystallographic data.
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20
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MacFarlane AA, Orriss G, Okun N, Meier M, Klonisch T, Khajehpour M, Stetefeld J. The pentameric channel of COMPcc in complex with different fatty acids. PLoS One 2012; 7:e48130. [PMID: 23133613 PMCID: PMC3487892 DOI: 10.1371/journal.pone.0048130] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 09/26/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND COMPcc forms a pentameric left-handed coiled coil that is known to bind hydrophilic signaling molecules such as vitamin D(3), and vitamin A. PRINCIPAL FINDINGS In an integrated approach we reveal the unique binding properties of COMPcc for saturated and unsaturated fatty acids. Our observations suggest that residues Met33 (gating pore), Thr40/Asn41 (water chamber) and Gln54 (electrostatic trap) are key elements for the binding of fatty acids by COMPcc. In addition, this work characterizes the binding of various fatty acids to COMPcc using fluorescence spectroscopy. Our findings reveal a binding trend within the hydrophobic channel of COMPcc, namely, that is driven by length of the methylene tail and incorporation of unsaturation. CONCLUSION/SIGNIFICANCE The unique binding properties imply that COMPcc may be involved in signalling functions in which hydrophilic ligands are involved. The pentameric channel is a unique carrier for lipophilic compounds. This opens the exciting possibility that COMPcc could be developed as a targeted drug delivery system.
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Affiliation(s)
| | - George Orriss
- Department of Chemistry, University of Manitoba, Canada
| | - Natalie Okun
- Department of Chemistry, University of Manitoba, Canada
| | - Markus Meier
- Department of Chemistry, University of Manitoba, Canada
| | - Thomas Klonisch
- Human Anatomy & Cell Science, University of Manitoba, Canada
| | | | - Jörg Stetefeld
- Department of Chemistry, Microbiology, Biochemistry and Medical Genetics, University of Manitoba, Canada
- * E-mail:
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Biochemical properties and crystal structure of a β-phenylalanine aminotransferase from Variovorax paradoxus. Appl Environ Microbiol 2012; 79:185-95. [PMID: 23087034 DOI: 10.1128/aem.02525-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
By selective enrichment, we isolated a bacterium that can use β-phenylalanine as a sole nitrogen source. It was identified by 16S rRNA gene sequencing as a strain of Variovorax paradoxus. Enzyme assays revealed an aminotransferase activity. Partial genome sequencing and screening of a cosmid DNA library resulted in the identification of a 1,302-bp aminotransferase gene, which encodes a 46,416-Da protein. The gene was cloned and overexpressed in Escherichia coli. The recombinant enzyme was purified and showed a specific activity of 17.5 U mg(-1) for (S)-β-phenylalanine at 30°C and 33 U mg(-1) at the optimum temperature of 55°C. The β-specific aminotransferase exhibits a broad substrate range, accepting ortho-, meta-, and para-substituted β-phenylalanine derivatives as amino donors and 2-oxoglutarate and pyruvate as amino acceptors. The enzyme is highly enantioselective toward (S)-β-phenylalanine (enantioselectivity [E], >100) and derivatives thereof with different substituents on the phenyl ring, allowing the kinetic resolution of various racemic β-amino acids to yield (R)-β-amino acids with >95% enantiomeric excess (ee). The crystal structures of the holoenzyme and of the enzyme in complex with the inhibitor 2-aminooxyacetate revealed structural similarity to the β-phenylalanine aminotransferase from Mesorhizobium sp. strain LUK. The crystal structure was used to rationalize the stereo- and regioselectivity of V. paradoxus aminotransferase and to define a sequence motif with which new aromatic β-amino acid-converting aminotransferases may be identified.
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Sorensen JL, Stetefeld J. Kinemage of action - proposed reaction mechanism of glutamate-1-semialdehyde aminomutase at an atomic level. Biochem Biophys Res Commun 2011; 413:572-6. [PMID: 21930115 DOI: 10.1016/j.bbrc.2011.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 09/01/2011] [Indexed: 11/19/2022]
Abstract
Glutamate-1-semialdehyde aminomutase (GSAM), a key enzyme in tetrapyrrole cofactor biosynthesis, performs a unique transamination on a single substrate. The substrate, glutamate-1-semialdehyde (GSA), undergoes a reaction that exchanges the position of an amine and a carbonyl group to produce 5-aminolevulinic acid (ALA). This transamination reaction is unique in the fact that is does not require an external cofactor to act as a nitrogen donor or acceptor in this transamination reaction. One of the other remarkable features of the catalytic mechanism is the release free in the enzyme active site of the intermediate 4,5-diaminovaleric acid (DAVA). The action of a gating loop prevents the escape of DAVA from the active site. In a MD simulation approach, using snapshots provided by X-ray crystallography and protein crystal absorption spectrometry data, the individual catalytic steps in this unique intramolecular transamination have been elucidated.
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Affiliation(s)
- John L Sorensen
- Department of Chemistry, University of Manitoba, Winnipeg, Canada R3T 2N2.
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23
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Clausnitzer D, Piepersberg W, Wehmeier U. The oxidoreductases LivQ and NeoQ are responsible for the different 6′-modifications in the aminoglycosides lividomycin and neomycin. J Appl Microbiol 2011; 111:642-51. [DOI: 10.1111/j.1365-2672.2011.05082.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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24
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Turbeville TD, Zhang J, Adams WC, Hunter GA, Ferreira GC. Functional asymmetry for the active sites of linked 5-aminolevulinate synthase and 8-amino-7-oxononanoate synthase. Arch Biochem Biophys 2011; 511:107-17. [PMID: 21600186 DOI: 10.1016/j.abb.2011.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 05/03/2011] [Accepted: 05/04/2011] [Indexed: 11/25/2022]
Abstract
5-Aminolevulinate synthase (ALAS) and 8-amino-7-oxononanoate synthase (AONS) are homodimeric members of the α-oxoamine synthase family of pyridoxal 5'-phosphate (PLP)-dependent enzymes. Previously, linking two ALAS subunits into a single polypeptide chain dimer yielded an enzyme (ALAS/ALAS) with a significantly greater turnover number than that of wild-type ALAS. To examine the contribution of each active site to the enzymatic activity of ALAS/ALAS, the catalytic lysine, which also covalently binds the PLP cofactor, was substituted with alanine in one of the active sites. Albeit the chemical rate for the pre-steady-state burst of ALA formation was identical in both active sites of ALAS/ALAS, the k(cat) values of the variants differed significantly (4.4±0.2 vs. 21.6±0.7 min(-1)) depending on which of the two active sites harbored the mutation. We propose that the functional asymmetry for the active sites of ALAS/ALAS stems from linking the enzyme subunits and the introduced intermolecular strain alters the protein conformational flexibility and rates of product release. Moreover, active site functional asymmetry extends to chimeric ALAS/AONS proteins, which while having a different oligomeric state, exhibit different rates of product release from the two ALAS and two AONS active sites due to the created intermolecular strain.
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Affiliation(s)
- Tracy D Turbeville
- Department of Molecular Medicine, College of Medicine, University of South Florida, Tampa, FL 33612, USA
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Ge H, Lv X, Fan J, Gao Y, Teng M, Niu L. Crystal structure of glutamate-1-semialdehyde aminotransferase from Bacillus subtilis with bound pyridoxamine-5'-phosphate. Biochem Biophys Res Commun 2010; 402:356-60. [PMID: 20946885 DOI: 10.1016/j.bbrc.2010.10.033] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 10/07/2010] [Indexed: 11/18/2022]
Abstract
Glutamate-1-semialdehyde aminotransferase (GSA-AT), also named glutamate-1-semialdehyde aminomutase (GSAM), a pyridoxamine-5'-phosphate (PMP)/pyridoxal-5'-phosphate (PLP) dependent enzyme, catalyses the transamination of the substrate glutamate-1-semialdehyde (GSA) to the product 5-Aminolevulinic acid (ALA) by an unusual intramolecular exchange of amino and oxo groups within the catalytic intermediate 4,5-diaminovalerate (DAVA). This paper presents the crystal structure of GSA-AT from Bacillus subtilis (GSA-ATBsu) in its PMP-bound form at 2.3Å resolution. The structure was determined by molecular replacement using the Synechococcus GSAM (GSAMSyn) structure as a search model. Unlike the previous reported GSAM/GSA-AT structures, GSA-ATBsu is a symmetric homodimer in the PMP-bound form, which shows the structural symmetry at the gating loop region with open state, as well as identical cofactor (PMP) binding in each monomer. This observation of PMP in combination with an "open" lid supports one characteristic feature for this enzyme, as the catalyzed reaction is believed to be initiated by PMP. Furthermore, the symmetry of GSA-ATBsu structure challenges the previously proposed negative cooperativity between monomers of this enzyme.
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Affiliation(s)
- Honghua Ge
- Modern Experiment Technology Center, Anhui University, Hefei, Anhui 230039, China.
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26
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Kale S, Jordan F. Conformational ensemble modulates cooperativity in the rate-determining catalytic step in the E1 component of the Escherichia coli pyruvate dehydrogenase multienzyme complex. J Biol Chem 2009; 284:33122-9. [PMID: 19801660 DOI: 10.1074/jbc.m109.065508] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cooperativity is extensively used by enzymes, particularly those acting at key metabolic branch points, to "fine tune" catalysis. Thus, cooperativity and enzyme catalysis are intimately linked, yet their linkage is poorly understood. Here we show that negative cooperativity in the rate-determining step in the E1 component of the Escherichia coli pyruvate dehydrogenase multienzyme complex is an outcome of redistribution of a "rate-promoting" conformational pre-equilibrium. An array of biophysical and biochemical studies indicates that non-catalytic but conserved residues directly regulate the redistribution. Furthermore, factors such as ligands and temperature, individually or in concert, also strongly influence the redistribution. As a consequence, these factors also exert their influence on catalysis by profoundly influencing the pre-equilibrium facilitated dynamics of communication between multienzyme components. Our observations suggest a mode of cooperativity in the E1 component that is consistent with the dynamical hypothesis shown to satisfactorily explain cooperativity in many well studied enzymes. The results point to the likely existence of multiple modes of communication between subunits when the entire class of thiamin diphosphate-dependent enzymes is considered.
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Affiliation(s)
- Sachin Kale
- Department of Chemistry, Rutgers University, Newark, New Jersey 07102, USA
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Orriss GL, Patel TR, Sorensen J, Stetefeld J. Absence of a catalytic water confers resistance to the neurotoxin gabaculine. FASEB J 2009; 24:404-14. [DOI: 10.1096/fj.09-138297] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- George L. Orriss
- Department of ChemistryUniversity of ManitobaWinnipegManitobaCanada
| | - Trushar R. Patel
- Department of ChemistryUniversity of ManitobaWinnipegManitobaCanada
| | - John Sorensen
- Department of ChemistryUniversity of ManitobaWinnipegManitobaCanada
| | - Jörg Stetefeld
- Department of ChemistryUniversity of ManitobaWinnipegManitobaCanada
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Heinemann IU, Jahn M, Jahn D. The biochemistry of heme biosynthesis. Arch Biochem Biophys 2008; 474:238-51. [PMID: 18314007 DOI: 10.1016/j.abb.2008.02.015] [Citation(s) in RCA: 226] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2008] [Revised: 02/14/2008] [Accepted: 02/14/2008] [Indexed: 02/03/2023]
Abstract
Heme is an integral part of proteins involved in multiple electron transport chains for energy recovery found in almost all forms of life. Moreover, heme is a cofactor of enzymes including catalases, peroxidases, cytochromes of the P(450) class and part of sensor molecules. Here the step-by-step biosynthesis of heme including involved enzymes, their mechanisms and detrimental health consequences caused by their failure are described. Unusual and challenging biochemistry including tRNA-dependent reactions, radical SAM enzymes and substrate derived cofactors are reported.
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Affiliation(s)
- Ilka U Heinemann
- Institute of Microbiology, Technical University of Braunschweig, Spielmannstr. 7, D-38106 Braunschweig, Germany
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