1
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Toci EM, Austin SL, Majumdar A, Woodcock HL, Freel Meyers CL. Disruption of an Active Site Network Leads to Activation of C2α-Lactylthiamin Diphosphate on the Antibacterial Target 1-Deoxy-d-xylulose-5-phosphate Synthase. Biochemistry 2024; 63:671-687. [PMID: 38393327 PMCID: PMC11015862 DOI: 10.1021/acs.biochem.3c00735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
The bacterial metabolic enzyme 1-deoxy-d-xylulose-5-phosphate synthase (DXPS) catalyzes the thiamin diphosphate (ThDP)-dependent formation of DXP from pyruvate and d-glyceraldehyde-3-phosphate (d-GAP). DXP is an essential bacteria-specific metabolite that feeds into the biosynthesis of isoprenoids, pyridoxal phosphate (PLP), and ThDP. DXPS catalyzes the activation of pyruvate to give the C2α-lactylThDP (LThDP) adduct that is long-lived on DXPS in a closed state in the absence of the cosubstrate. Binding of d-GAP shifts the DXPS-LThDP complex to an open state which coincides with LThDP decarboxylation. This gated mechanism distinguishes DXPS in ThDP enzymology. How LThDP persists on DXPS in the absence of cosubstrate, while other pyruvate decarboxylases readily activate LThDP for decarboxylation, is a long-standing question in the field. We propose that an active site network functions to prevent LThDP activation on DXPS until the cosubstrate binds. Binding of d-GAP coincides with a conformational shift and disrupts the network causing changes in the active site that promote LThDP activation. Here, we show that the substitution of putative network residues, as well as nearby residues believed to contribute to network charge distribution, predictably affects LThDP reactivity. Substitutions predicted to disrupt the network have the effect to activate LThDP for decarboxylation, resulting in CO2 and acetate production. In contrast, a substitution predicted to strengthen the network fails to activate LThDP and has the effect to shift DXPS toward the closed state. Network-disrupting substitutions near the carboxylate of LThDP also have a pronounced effect to shift DXPS to an open state. These results offer initial insights to explain the long-lived LThDP intermediate and its activation through disruption of an active site network, which is unique to DXPS. These findings have important implications for DXPS function in bacteria and its development as an antibacterial target.
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Affiliation(s)
- Eucolona M Toci
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Steven L Austin
- Department of Chemistry, University of South Florida, Tampa, Florida 33620, United States
| | - Ananya Majumdar
- Biomolecular NMR Center, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - H Lee Woodcock
- Department of Chemistry, University of South Florida, Tampa, Florida 33620, United States
| | - Caren L Freel Meyers
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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2
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Daniel-Ivad PG, Van Lanen S, Ryan KS. Structure of the Oxygen, Pyridoxal Phosphate-Dependent Capuramycin Biosynthetic Protein Cap15. Biochemistry 2023; 62:2611-2621. [PMID: 37556254 DOI: 10.1021/acs.biochem.3c00216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
Pyridoxal phosphate-dependent enzymes able to use oxygen as a co-substrate have emerged in multiple protein families. Here, we use crystallography to solve the 2.40 Å resolution crystal structure of Cap15, a nucleoside biosynthetic enzyme that catalyzes the oxidative decarboxylation of glycyl uridine. Our structural study captures the internal aldimine, pinpointing the active site lysine as K230 and showing the site of phosphate binding. Our docking studies reveal how Cap15 is able to catalyze a stereoselective deprotonation reaction, and bioinformatic analysis reveals active site residues that distinguish Cap15 from the structurally related d-glucosaminate-6-phosphate ammonia lyase and l-seryl-tRNA(Sec) selenium transferase (SelA). Our work provides the structural basis for further mechanistic investigation of a unique biosynthetic enzyme and provides a blueprint for understanding how oxygen reactivity emerged in the SelA-like protein family.
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Affiliation(s)
- Phillip G Daniel-Ivad
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Steven Van Lanen
- Pharmaceutical Sciences Department, University of Kentucky, Lexington, Kentucky 40506, United States
| | - Katherine S Ryan
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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3
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Johnston ML, Freel Meyers CL. Revealing Donor Substrate-Dependent Mechanistic Control on DXPS, an Enzyme in Bacterial Central Metabolism. Biochemistry 2021; 60:929-939. [PMID: 33660509 PMCID: PMC8015787 DOI: 10.1021/acs.biochem.1c00019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The thiamin diphosphate-dependent enzyme 1-deoxy-d-xylulose 5-phosphate synthase (DXPS) catalyzes the formation of DXP from pyruvate (donor) and d-glyceraldehyde 3-phosphate (d-GAP, acceptor). DXPS is essential in bacteria but absent in human metabolism, highlighting it as a potential antibacterial drug target. The enzyme possesses unique structural and mechanistic features that enable development of selective inhibition strategies and raise interesting questions about DXPS function in bacterial pathogens. DXPS distinguishes itself within the ThDP enzyme class by its exceptionally large active site and random sequential mechanism in DXP formation. In addition, DXPS displays catalytic promiscuity and relaxed acceptor substrate specificity, yet previous studies have suggested a preference for pyruvate as the donor substrate when d-GAP is the acceptor substrate. However, such donor specificity studies are potentially hindered by a lack of knowledge about specific, alternative donor-acceptor pairs. In this study, we exploited the promiscuous oxygenase activity of DXPS to uncover alternative donor substrates for DXPS. Characterization of glycolaldehyde, hydroxypyruvate, and ketobutyrate as donor substrates revealed differences in stabilization of enzyme-bound intermediates and acceptor substrate usage, illustrating the influence of the donor substrate on reaction mechanism and acceptor specificity. In addition, we found that DXPS prevents abortive acetyl-ThDP formation from a DHEThDP carbanion/enamine intermediate, similar to transketolase, supporting the potential physiological relevance of this intermediate on DXPS. Taken together, these results offer clues toward alternative roles for DXPS in bacterial pathogen metabolism.
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Affiliation(s)
- Melanie L Johnston
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Caren L Freel Meyers
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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4
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Oxygen reactivity with pyridoxal 5'-phosphate enzymes: biochemical implications and functional relevance. Amino Acids 2020; 52:1089-1105. [PMID: 32844248 PMCID: PMC7497351 DOI: 10.1007/s00726-020-02885-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/18/2020] [Indexed: 12/29/2022]
Abstract
The versatility of reactions catalyzed by pyridoxal 5'-phosphate (PLP) enzymes is largely due to the chemistry of their extraordinary catalyst. PLP is necessary for many reactions involving amino acids. Reaction specificity is controlled by the orientation of the external aldimine intermediate that is formed upon addition of the amino acidic substrate to the coenzyme. The breakage of a specific bond of the external aldimine gives rise to a carbanionic intermediate. From this point, the different reaction pathways diverge leading to multiple activities: transamination, decarboxylation, racemization, elimination, and synthesis. A significant novelty appeared approximately 30 years ago when it was reported that some PLP-dependent decarboxylases are able to consume molecular oxygen transforming an amino acid into a carbonyl compound. These side paracatalytic reactions could be particularly relevant for human health, also considering that some of these enzymes are responsible for the synthesis of important neurotransmitters such as γ-aminobutyric acid, dopamine, and serotonin, whose dysregulation under oxidative conditions could have important implications in neurodegenerative states. However, the reactivity of PLP enzymes with dioxygen is not confined to mammals/animals. In fact, some plant PLP decarboxylases have been reported to catalyze oxidative reactions producing carbonyl compounds. Moreover, other recent reports revealed the existence of new oxidase activities catalyzed by new PLP enzymes, MppP, RohP, Ind4, CcbF, PvdN, Cap15, and CuaB. These PLP enzymes belong to the bacterial and fungal kingdoms and are present in organisms synthesizing bioactive compounds. These new PLP activities are not paracatalytic and could only scratch the surface on a wider and unexpected catalytic capability of PLP enzymes.
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5
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Structural basis for divergent and convergent evolution of catalytic machineries in plant aromatic amino acid decarboxylase proteins. Proc Natl Acad Sci U S A 2020; 117:10806-10817. [PMID: 32371491 DOI: 10.1073/pnas.1920097117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Radiation of the plant pyridoxal 5'-phosphate (PLP)-dependent aromatic l-amino acid decarboxylase (AAAD) family has yielded an array of paralogous enzymes exhibiting divergent substrate preferences and catalytic mechanisms. Plant AAADs catalyze either the decarboxylation or decarboxylation-dependent oxidative deamination of aromatic l-amino acids to produce aromatic monoamines or aromatic acetaldehydes, respectively. These compounds serve as key precursors for the biosynthesis of several important classes of plant natural products, including indole alkaloids, benzylisoquinoline alkaloids, hydroxycinnamic acid amides, phenylacetaldehyde-derived floral volatiles, and tyrosol derivatives. Here, we present the crystal structures of four functionally distinct plant AAAD paralogs. Through structural and functional analyses, we identify variable structural features of the substrate-binding pocket that underlie the divergent evolution of substrate selectivity toward indole, phenyl, or hydroxyphenyl amino acids in plant AAADs. Moreover, we describe two mechanistic classes of independently arising mutations in AAAD paralogs leading to the convergent evolution of the derived aldehyde synthase activity. Applying knowledge learned from this study, we successfully engineered a shortened benzylisoquinoline alkaloid pathway to produce (S)-norcoclaurine in yeast. This work highlights the pliability of the AAAD fold that allows change of substrate selectivity and access to alternative catalytic mechanisms with only a few mutations.
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6
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Hoffarth ER, Rothchild KW, Ryan KS. Emergence of oxygen- and pyridoxal phosphate-dependent reactions. FEBS J 2020; 287:1403-1428. [PMID: 32142210 DOI: 10.1111/febs.15277] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 11/29/2019] [Accepted: 03/03/2020] [Indexed: 12/21/2022]
Abstract
Pyridoxal 5'-phosphate (PLP) is an organic cofactor employed by ~ 4% of enzymes. The structure of the PLP cofactor allows for the stabilization of carbanions through resonance. A small number of PLP-dependent enzymes employ molecular oxygen as a cosubstrate. Here, we review the biological roles and possible mechanisms of these enzymes, and we observe that these enzymes are found in multiple protein families, suggesting that reaction with oxygen might have emerged de novo in several protein families and thus could be directed to emerge again through laboratory evolution experiments.
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Affiliation(s)
- Elesha R Hoffarth
- Department of Chemistry, University of British Columbia, Vancouver, BC, Canada
| | | | - Katherine S Ryan
- Department of Chemistry, University of British Columbia, Vancouver, BC, Canada
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Bunik VI. Redox-Driven Signaling: 2-Oxo Acid Dehydrogenase Complexes as Sensors and Transmitters of Metabolic Imbalance. Antioxid Redox Signal 2019; 30:1911-1947. [PMID: 30187773 DOI: 10.1089/ars.2017.7311] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
SIGNIFICANCE This article develops a holistic view on production of reactive oxygen species (ROS) by 2-oxo acid dehydrogenase complexes. Recent Advances: Catalytic and structural properties of the complexes and their components evolved to minimize damaging effects of side reactions, including ROS generation, simultaneously exploiting the reactions for homeostatic signaling. CRITICAL ISSUES Side reactions of the complexes, characterized in vitro, are analyzed in view of protein interactions and conditions in vivo. Quantitative data support prevalence of the forward 2-oxo acid oxidation over the backward NADH oxidation in feeding physiologically significant ROS production by the complexes. Special focus on interactions between the active sites within 2-oxo acid dehydrogenase complexes highlights the central relevance of the complex-bound thiyl radicals in regulation of and signaling by complex-generated ROS. The thiyl radicals arise when dihydrolipoyl residues of the complexes regenerate FADH2 from the flavin semiquinone coproduced with superoxide anion radical in 1e- oxidation of FADH2 by molecular oxygen. FUTURE DIRECTIONS Interaction of 2-oxo acid dehydrogenase complexes with thioredoxins (TRXs), peroxiredoxins, and glutaredoxins mediates scavenging of the thiyl radicals and ROS generated by the complexes, underlying signaling of disproportional availability of 2-oxo acids, CoA, and NAD+ in key metabolic branch points through thiol/disulfide exchange and medically important hypoxia-inducible factor, mammalian target of rapamycin (mTOR), poly (ADP-ribose) polymerase, and sirtuins. High reactivity of the coproduced ROS and thiyl radicals to iron/sulfur clusters and nitric oxide, peroxynitrite reductase activity of peroxiredoxins and transnitrosylating function of thioredoxin, implicate the side reactions of 2-oxo acid dehydrogenase complexes in nitric oxide-dependent signaling and damage.
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Affiliation(s)
- Victoria I Bunik
- 1 Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation.,2 Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russian Federation
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8
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Du YL, Ryan KS. Pyridoxal phosphate-dependent reactions in the biosynthesis of natural products. Nat Prod Rep 2019; 36:430-457. [DOI: 10.1039/c8np00049b] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We review reactions catalyzed by pyridoxal phosphate-dependent enzymes, highlighting enzymes reported in the recent natural product biosynthetic literature.
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Affiliation(s)
- Yi-Ling Du
- Institute of Pharmaceutical Biotechnology
- Zhejiang University School of Medicine
- Hangzhou
- China
| | - Katherine S. Ryan
- Department of Chemistry
- University of British Columbia
- Vancouver
- Canada
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Two active site arginines are critical determinants of substrate binding and catalysis in MenD: a thiamine-dependent enzyme in menaquinone biosynthesis. Biochem J 2018; 475:3651-3667. [DOI: 10.1042/bcj20180548] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 10/10/2018] [Accepted: 10/17/2018] [Indexed: 11/17/2022]
Abstract
The bacterial enzyme MenD, or 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate (SEPHCHC) synthase, catalyzes an essential Stetter reaction in menaquinone (vitamin K2) biosynthesis via thiamine diphosphate (ThDP)-bound tetrahedral post-decarboxylation intermediates. The detailed mechanism of this intermediate chemistry, however, is still poorly understood, but of significant interest given that menaquinone is an essential electron transporter in many pathogenic bacteria. Here, we used site-directed mutagenesis, enzyme kinetic assays, and protein crystallography to reveal an active–inactive intermediate equilibrium in MenD catalysis and its modulation by two conserved active site arginine residues. We observed that these conserved residues play a key role in shifting the equilibrium to the active intermediate by orienting the C2-succinyl group of the intermediates through strong ionic hydrogen bonding. We found that when this interaction is moderately weakened by amino acid substitutions, the resulting proteins are catalytically competent with the C2-succinyl group taking either the active or the inactive orientation in the post-decarboxylation intermediate. When this hydrogen-bonding interaction was strongly weakened, the succinyl group was re-oriented by 180° relative to the native intermediate, resulting in the reversal of the stereochemistry at the reaction center that disabled catalysis. Interestingly, this inactive intermediate was formed with a distinct kinetic behavior, likely as a result of a non-native mode of enzyme–substrate interaction. The mechanistic insights gained from these findings improve our understanding of the new ThDP-dependent catalysis. More importantly, the non-native-binding site of the inactive MenD intermediate uncovered here provides a new target for the development of antibiotics.
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10
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Commercial AHAS-inhibiting herbicides are promising drug leads for the treatment of human fungal pathogenic infections. Proc Natl Acad Sci U S A 2018; 115:E9649-E9658. [PMID: 30249642 DOI: 10.1073/pnas.1809422115] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The increased prevalence of drug-resistant human pathogenic fungal diseases poses a major threat to global human health. Thus, new drugs are urgently required to combat these infections. Here, we demonstrate that acetohydroxyacid synthase (AHAS), the first enzyme in the branched-chain amino acid biosynthesis pathway, is a promising new target for antifungal drug discovery. First, we show that several AHAS inhibitors developed as commercial herbicides are powerful accumulative inhibitors of Candida albicans AHAS (K i values as low as 800 pM) and have determined high-resolution crystal structures of this enzyme in complex with several of these herbicides. In addition, we have demonstrated that chlorimuron ethyl (CE), a member of the sulfonylurea herbicide family, has potent antifungal activity against five different Candida species and Cryptococcus neoformans (with minimum inhibitory concentration, 50% values as low as 7 nM). Furthermore, in these assays, we have shown CE and itraconazole (a P450 inhibitor) can act synergistically to further improve potency. Finally, we show in Candida albicans-infected mice that CE is highly effective in clearing pathogenic fungal burden in the lungs, liver, and spleen, thus reducing overall mortality rates. Therefore, in view of their low toxicity to human cells, AHAS inhibitors represent a new class of antifungal drug candidates.
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11
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Qin M, Song H, Dai X, Chan C, Chan W, Guo Z. Single‐Turnover Kinetics Reveal a Distinct Mode of Thiamine Diphosphate‐Dependent Catalysis in Vitamin K Biosynthesis. Chembiochem 2018; 19:1514-1522. [DOI: 10.1002/cbic.201800143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Indexed: 01/09/2023]
Affiliation(s)
- Mingming Qin
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Haigang Song
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- Present address: Division of Structural BiologyWellcome Trust Centre of Human GenomicsUniversity of Oxford Roosevelt Drive Oxford OX3 7BN UK
| | - Xin Dai
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Chi‐Kong Chan
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- Environmental Science ProgramThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Wan Chan
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- Environmental Science ProgramThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Zhihong Guo
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
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12
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DeColli AA, Nemeria NS, Majumdar A, Gerfen GJ, Jordan F, Freel Meyers CL. Oxidative decarboxylation of pyruvate by 1-deoxy-d-xyulose 5-phosphate synthase, a central metabolic enzyme in bacteria. J Biol Chem 2018; 293:10857-10869. [PMID: 29784878 DOI: 10.1074/jbc.ra118.001980] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 05/17/2018] [Indexed: 01/06/2023] Open
Abstract
The underexploited antibacterial target 1-deoxy-d-xyluose 5-phosphate (DXP) synthase catalyzes the thiamin diphosphate (ThDP)-dependent formation of DXP from pyruvate and d-glyceraldehyde 3-phosphate (d-GAP). DXP is an essential intermediate in the biosynthesis of ThDP, pyridoxal phosphate, and isoprenoids in many pathogenic bacteria. DXP synthase catalyzes a distinct mechanism in ThDP decarboxylative enzymology in which the first enzyme-bound pre-decarboxylation intermediate, C2α-lactyl-ThDP (LThDP), is stabilized by DXP synthase in the absence of d-GAP, and d-GAP then induces efficient LThDP decarboxylation. Despite the observed LThDP accumulation and lack of evidence for C2α-carbanion formation in the absence of d-GAP, CO2 is released at appreciable levels under these conditions. Here, seeking to resolve these conflicting observations, we show that DXP synthase catalyzes the oxidative decarboxylation of pyruvate under conditions in which LThDP accumulates. O2-dependent LThDP decarboxylation led to one-electron transfer from the C2α-carbanion/enamine to O2, with intermediate ThDP-enamine radical formation, followed by peracetic acid formation en route to acetate. Thus, LThDP formation and decarboxylation and DXP formation were studied under anaerobic conditions. Our results support a model in which O2-dependent LThDP decarboxylation and peracetic acid formation occur in the absence of d-GAP, decreasing the levels of pyruvate and O2 in solution. The relative pyruvate and O2 concentrations then dictate the extent of LThDP accumulation, and its buildup can be observed when [pyruvate] > [O2]. The finding that O2 acts as a structurally distinct trigger of LThDP decarboxylation supports the hypothesis that a mechanism involving small molecule-dependent LThDP decarboxylation equips DXP synthase for diverse, yet uncharacterized cellular functions.
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Affiliation(s)
| | - Natalia S Nemeria
- the Department of Chemistry, Rutgers University, Newark, New Jersey 07102, and
| | - Ananya Majumdar
- Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Gary J Gerfen
- the Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Frank Jordan
- the Department of Chemistry, Rutgers University, Newark, New Jersey 07102, and
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13
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Bathellier C, Tcherkez G, Lorimer GH, Farquhar GD. Rubisco is not really so bad. PLANT, CELL & ENVIRONMENT 2018; 41:705-716. [PMID: 29359811 DOI: 10.1111/pce.13149] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 01/09/2018] [Accepted: 01/09/2018] [Indexed: 05/19/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the most widespread carboxylating enzyme in autotrophic organisms. Its kinetic and structural properties have been intensively studied for more than half a century. Yet important aspects of the catalytic mechanism remain poorly understood, especially the oxygenase reaction. Because of its relatively modest turnover rate (a few catalytic events per second) and the competitive inhibition by oxygen, Rubisco is often viewed as an inefficient catalyst for CO2 fixation. Considerable efforts have been devoted to improving its catalytic efficiency, so far without success. In this review, we re-examine Rubisco's catalytic performance by comparison with other chemically related enzymes. We find that Rubisco is not especially slow. Furthermore, considering both the nature and the complexity of the chemical reaction, its kinetic properties are unremarkable. Although not unique to Rubisco, oxygenation is not systematically observed in enolate and enamine forming enzymes and cannot be considered as an inevitable consequence of the mechanism. It is more likely the result of a compromise between chemical and metabolic imperatives. We argue that a better description of Rubisco mechanism is still required to better understand the link between CO2 and O2 reactivity and the rationale of Rubisco diversification and evolution.
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Affiliation(s)
- Camille Bathellier
- Research School of Biology, College of Science, Australian National University, Canberra, 2601, ACT, Australia
| | - Guillaume Tcherkez
- Research School of Biology, College of Science, Australian National University, Canberra, 2601, ACT, Australia
| | - George H Lorimer
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 27042, USA
| | - Graham D Farquhar
- Research School of Biology, College of Science, Australian National University, Canberra, 2601, ACT, Australia
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14
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Pyridoxal-5'-phosphate as an oxygenase cofactor: Discovery of a carboxamide-forming, α-amino acid monooxygenase-decarboxylase. Proc Natl Acad Sci U S A 2018; 115:974-979. [PMID: 29343643 DOI: 10.1073/pnas.1718667115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Capuramycins are antimycobacterial antibiotics that consist of a modified nucleoside named uridine-5'-carboxamide (CarU). Previous biochemical studies have revealed that CarU is derived from UMP, which is first converted to uridine-5'-aldehyde in a reaction catalyzed by the dioxygenase CapA and subsequently to 5'-C-glycyluridine (GlyU), an unusual β-hydroxy-α-amino acid, in a reaction catalyzed by the pyridoxal-5'-phosphate (PLP)-dependent transaldolase CapH. The remaining steps that are necessary to furnish CarU include decarboxylation, O atom insertion, and oxidation. We demonstrate that Cap15, which has sequence similarity to proteins annotated as bacterial, PLP-dependent l-seryl-tRNA(Sec) selenium transferases, is the sole catalyst responsible for complete conversion of GlyU to CarU. Using a complementary panel of in vitro assays, Cap15 is shown to be dependent upon substrates O2 and (5'S,6'R)-GlyU, the latter of which was unexpected given that (5'S,6'S)-GlyU is the isomeric product of the transaldolase CapH. The two products of Cap15 are identified as the carboxamide-containing CarU and CO2 While known enzymes that catalyze this type of chemistry, namely α-amino acid 2-monooxygenase, utilize flavin adenine dinucleotide as the redox cofactor, Cap15 remarkably requires only PLP. Furthermore, Cap15 does not produce hydrogen peroxide and is shown to directly incorporate a single O atom from O2 into the product CarU and thus is an authentic PLP-dependent monooxygenase. In addition to these unusual discoveries, Cap15 activity is revealed to be dependent upon the inclusion of phosphate. The biochemical characteristics along with initiatory mechanistic studies of Cap15 are reported, which has allowed us to assign Cap15 as a PLP-dependent (5'S,6'R)-GlyU:O2 monooxygenase-decarboxylase.
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15
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Lonhienne T, Garcia MD, Noble C, Harmer J, Fraser JA, Williams CM, Guddat LW. High Resolution Crystal Structures of the Acetohydroxyacid Synthase‐Pyruvate Complex Provide New Insights into Its Catalytic Mechanism. ChemistrySelect 2017. [DOI: 10.1002/slct.201702128] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Thierry Lonhienne
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Mario D. Garcia
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Chris Noble
- Centre for Advanced Imaging The University of Queensland Brisbane 4072 QLD Australia
| | - Jeffrey Harmer
- Centre for Advanced Imaging The University of Queensland Brisbane 4072 QLD Australia
| | - James A. Fraser
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Craig M. Williams
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Luke W. Guddat
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
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16
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Pan D, Li QX, Lin Z, Chen Z, Tang W, Pan C, Tan H, Zeng D. Interactions between salicylic acid and antioxidant enzymes tilting the balance of H 2O 2 from photorespiration in non-target crops under halosulfuron-methyl stress. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2017; 143:214-223. [PMID: 29183595 DOI: 10.1016/j.pestbp.2017.09.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 07/14/2017] [Accepted: 09/14/2017] [Indexed: 06/07/2023]
Abstract
Halosulfuron-methyl (HSM) is a safe, selective and effective sulfonylurea herbicide (SU) for the control of sedge and broadleaf weeds in sugarcane, corn, tomato, and other crops. The primary site of action is acetolactate synthase (ALS), a key enzyme of branched chain amino acids (BCAAs) synthesis. In addition to ALS inhibition, BCAAs deficiencies and oxidative damage may be involved in toxic effects of SUs. However, secondary targets of HSM relevant to plant physiological responses are unclear. In the present study, comparative growth inhibition and peroxidization injury between sensitive and tolerance crops were observed at biochemical and physiological levels suggesting involvement of H2O2, ethylene, salicylic acid (SA) in the oxidative stress responses to HSM. HSM caused accumulation of H2O2, stimulated photorespiration and consequent accumulation of SA that worsened the peroxidization injury to the sensitive C3 plant soybean (Glycine max). The growth inhibition at low concentrations of HSM could be lessened by supplementary BCAAs, reactive oxygen species scavengers or ethylene inducers, whereas the oxidation damage at high concentrations of HSM could not be reversed and ultimately lead to plant death. H2O2 at a low level stimulated the antioxidase system including glutathione S-transferase activities in the HSM-tolerant C4 maize (Zea mays), which contributes to HSM tolerance. H2O2 plays an important role on HSM stress responses in both HSM-sensitive and HSM-tolerant soybean and maize.
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Affiliation(s)
- Dongjin Pan
- Guangxi Key Laboratory of Agric-Environment and Agric-Products Safety, Agricultural College, Guangxi University, Nanning, Guangxi 530005, China; Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, United States
| | - Qing X Li
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, United States
| | - Zhangxing Lin
- Guangxi Key Laboratory of Agric-Environment and Agric-Products Safety, Agricultural College, Guangxi University, Nanning, Guangxi 530005, China
| | - Zhaojie Chen
- Guangxi Key Laboratory of Agric-Environment and Agric-Products Safety, Agricultural College, Guangxi University, Nanning, Guangxi 530005, China
| | - Wenwei Tang
- Guangxi Key Laboratory of Agric-Environment and Agric-Products Safety, Agricultural College, Guangxi University, Nanning, Guangxi 530005, China
| | - Canping Pan
- College of Sciences, China Agricultural University, Beijing 100193, China
| | - Huihua Tan
- Guangxi Key Laboratory of Agric-Environment and Agric-Products Safety, Agricultural College, Guangxi University, Nanning, Guangxi 530005, China.
| | - Dongqiang Zeng
- Guangxi Key Laboratory of Agric-Environment and Agric-Products Safety, Agricultural College, Guangxi University, Nanning, Guangxi 530005, China.
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Eram MS, Ma K. Pyruvate decarboxylase activity of the acetohydroxyacid synthase of Thermotoga maritima. Biochem Biophys Rep 2016; 7:394-399. [PMID: 28955930 PMCID: PMC5613635 DOI: 10.1016/j.bbrep.2016.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 06/20/2016] [Accepted: 07/13/2016] [Indexed: 11/30/2022] Open
Abstract
Acetohydroxyacid synthase (AHAS) catalyzes the production of acetolactate from pyruvate. The enzyme from the hyperthermophilic bacterium Thermotoga maritima has been purified and characterized (kcat ~100 s−1). It was found that the same enzyme also had the ability to catalyze the production of acetaldehyde and CO2 from pyruvate, an activity of pyruvate decarboxylase (PDC) at a rate approximately 10% of its AHAS activity. Compared to the catalytic subunit, reconstitution of the individually expressed and purified catalytic and regulatory subunits of the AHAS stimulated both activities of PDC and AHAS. Both activities had similar pH and temperature profiles with an optimal pH of 7.0 and temperature of 85 °C. The enzyme kinetic parameters were determined, however, it showed a non-Michaelis-Menten kinetics for pyruvate only. This is the first report on the PDC activity of an AHAS and the second bifunctional enzyme that might be involved in the production of ethanol from pyruvate in hyperthermophilic microorganisms. The acetohydroxyacid synthase of T. maritima has pyruvate decarboxylase activity The AHAS and PDC activities share the same temperature and pH optima Reconstitution of the catalytic and regulatory subunits increases both PDC and AHAS activities
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Affiliation(s)
- Mohammad S Eram
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Kesen Ma
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
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Lonhienne T, Nouwens A, Williams CM, Fraser JA, Lee Y, West NP, Guddat LW. Commercial Herbicides Can Trigger the Oxidative Inactivation of Acetohydroxyacid Synthase. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201511985] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Thierry Lonhienne
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Amanda Nouwens
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Craig M. Williams
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - James A. Fraser
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Yu‐Ting Lee
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Nicholas P. West
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Luke W. Guddat
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
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19
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Lonhienne T, Nouwens A, Williams CM, Fraser JA, Lee Y, West NP, Guddat LW. Commercial Herbicides Can Trigger the Oxidative Inactivation of Acetohydroxyacid Synthase. Angew Chem Int Ed Engl 2016; 55:4247-51. [DOI: 10.1002/anie.201511985] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 01/22/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Thierry Lonhienne
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Amanda Nouwens
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Craig M. Williams
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - James A. Fraser
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Yu‐Ting Lee
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Nicholas P. West
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
| | - Luke W. Guddat
- School of Chemistry and Molecular Biosciences The University of Queensland Brisbane 4072 QLD Australia
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20
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Du YL, Singh R, Alkhalaf LM, Kuatsjah E, He HY, Eltis LD, Ryan KS. A pyridoxal phosphate–dependent enzyme that oxidizes an unactivated carbon-carbon bond. Nat Chem Biol 2016; 12:194-9. [DOI: 10.1038/nchembio.2009] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 12/02/2015] [Indexed: 11/09/2022]
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21
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Li H, Liu N, Wang WT, Wang JY, Gao WY. Cloning and characterization of GST fusion tag stabilized large subunit of Escherichia coli acetohydroxyacid synthase I. J Biosci Bioeng 2016; 121:21-26. [DOI: 10.1016/j.jbiosc.2015.05.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 05/07/2015] [Accepted: 05/18/2015] [Indexed: 10/22/2022]
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22
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Latent luciferase activity in the fruit fly revealed by a synthetic luciferin. Proc Natl Acad Sci U S A 2014; 111:4443-8. [PMID: 24616520 DOI: 10.1073/pnas.1319300111] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Beetle luciferases are thought to have evolved from fatty acyl-CoA synthetases present in all insects. Both classes of enzymes activate fatty acids with ATP to form acyl-adenylate intermediates, but only luciferases can activate and oxidize d-luciferin to emit light. Here we show that the Drosophila fatty acyl-CoA synthetase CG6178, which cannot use d-luciferin as a substrate, is able to catalyze light emission from the synthetic luciferin analog CycLuc2. Bioluminescence can be detected from the purified protein, live Drosophila Schneider 2 cells, and from mammalian cells transfected with CG6178. Thus, the nonluminescent fruit fly possesses an inherent capacity for bioluminescence that is only revealed upon treatment with a xenobiotic molecule. This result expands the scope of bioluminescence and demonstrates that the introduction of a new substrate can unmask latent enzymatic activity that differs significantly from an enzyme's normal function without requiring mutation.
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23
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Czekster CM, Blanchard JS. One substrate, five products: reactions catalyzed by the dihydroneopterin aldolase from Mycobacterium tuberculosis. J Am Chem Soc 2012; 134:19758-71. [PMID: 23150985 DOI: 10.1021/ja308350f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Tetrahydrofolate cofactors are required for one carbon transfer reaction involved in the synthesis of purines, amino acids, and thymidine. Inhibition of tetrahydrofolate biosynthesis is a powerful therapeutic strategy in the treatment of several diseases, and the possibility of using antifolates to inhibit enzymes from Mycobacterium tuberculosis has been explored. This work focuses on the study of the first enzyme in tetrahydrofolate biosynthesis that is unique to bacteria, dihydroneopterin aldolase (MtDHNA). This enzyme requires no metals or cofactors and does not form a protein-mediated Schiff base with the substrate, unlike most aldolases. Here, we were able to demonstrate that the reaction catalyzed by MtDHNA generates three different pterin products, one of which is not produced by other wild-type DHNAs. The enzyme-substrate complex partitions 51% in the first turnover to form the aldolase products, 24% to the epimerase product and 25% to the oxygenase products. The aldolase reaction is strongly pH dependent, and apparent pK(a) values were obtained for the first time for this class of enzyme. Furthermore, chemistry is rate limiting for the aldolase reaction, and the analysis of solvent kinetic isotope effects in steady-state and pre-steady-state conditions, combined with proton inventory studies, revealed that two protons and a likely solvent contribution are involved in formation and breakage of a common intermediate. This study provides information about the plasticity required from a catalyst that possesses high substrate specificity while being capable of utilizing two distinct epimers with the same efficiency to generate five distinct products.
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Affiliation(s)
- Clarissa M Czekster
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461, United States
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24
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Belenky I, Steinmetz A, Vyazmensky M, Barak Z, Tittmann K, Chipman DM. Many of the functional differences between acetohydroxyacid synthase (AHAS) isozyme I and other AHASs are a result of the rapid formation and breakdown of the covalent acetolactate-thiamin diphosphate adduct in AHAS I. FEBS J 2012; 279:1967-79. [DOI: 10.1111/j.1742-4658.2012.08577.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Gedi V, Yoon MY. Bacterial acetohydroxyacid synthase and its inhibitors - a summary of their structure, biological activity and current status. FEBS J 2012; 279:946-63. [DOI: 10.1111/j.1742-4658.2012.08505.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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26
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Bunik VI, Schloss JV, Pinto JT, Dudareva N, Cooper AJL. A survey of oxidative paracatalytic reactions catalyzed by enzymes that generate carbanionic intermediates: implications for ROS production, cancer etiology, and neurodegenerative diseases. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2011; 77:307-60. [PMID: 21692372 DOI: 10.1002/9780470920541.ch7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Victoria I Bunik
- School of Bioinformatics and Bioengineering, and Belozersky Institute of Physico-Chemical Biology, Moscow Lomonosov State University, Moscow, Russian Federation
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27
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Meyer D, Walter L, Kolter G, Pohl M, Müller M, Tittmann K. Conversion of Pyruvate Decarboxylase into an Enantioselective Carboligase with Biosynthetic Potential. J Am Chem Soc 2011; 133:3609-16. [PMID: 21341803 DOI: 10.1021/ja110236w] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Danilo Meyer
- Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, Ernst-Caspari-Haus, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Strasse 3, D-06120 Halle/Saale, Germany
| | - Lydia Walter
- Institute of Pharmaceutical Sciences, Albert-Ludwigs-University Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Geraldine Kolter
- Institute of Biotechnology 2, Research Centre Jülich, 52425 Jülich, Germany
| | - Martina Pohl
- Institute of Biotechnology 2, Research Centre Jülich, 52425 Jülich, Germany
| | - Michael Müller
- Institute of Pharmaceutical Sciences, Albert-Ludwigs-University Freiburg, 79104 Freiburg im Breisgau, Germany
| | - Kai Tittmann
- Albrecht-von-Haller-Institute for Plant Sciences and Göttingen Center for Molecular Biosciences, Georg-August-University Göttingen, Ernst-Caspari-Haus, Justus-von-Liebig-Weg 11, D-37077 Göttingen, Germany
- Institute of Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Strasse 3, D-06120 Halle/Saale, Germany
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28
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Grocholski T, Koskiniemi H, Lindqvist Y, Mäntsälä P, Niemi J, Schneider G. Crystal structure of the cofactor-independent monooxygenase SnoaB from Streptomyces nogalater: implications for the reaction mechanism. Biochemistry 2010; 49:934-44. [PMID: 20052967 DOI: 10.1021/bi901985b] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
SnoaB is a cofactor-independent monooxygenase that catalyzes the conversion of 12-deoxynogalonic acid to nogalonic acid in the biosynthesis of the aromatic polyketide nogalamycin in Streptomyces nogalater. In vitro (18)O(2) experiments establish that the oxygen atom incorporated into the substrate is derived from molecular oxygen. The crystal structure of the enzyme was determined in two different space groups to 1.7 and 1.9 A resolution, respectively. The enzyme displays the ferredoxin fold, with the characteristic beta-strand exchange at the dimer interface. The crystal structures reveal a putative catalytic triad involving two asparagine residues, Asn18 and Asn63, and a water molecule, which may play important roles in the enzymatic reaction. Site-directed mutagenesis experiments, replacing the two asparagines individually by alanine, led to a 100-fold drop in enzymatic activity. Replacement of an invariant tryptophan residue in the active site of the enzyme by phenylalanine also resulted in an enzyme variant with about 1% residual activity. Taken together, our findings are most consistent with a carbanion mechanism where the deprotonated substrate reacts with molecular oxygen via one electron transfer and formation of a caged radical.
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Affiliation(s)
- Thadee Grocholski
- Department of Biochemistry and Food Chemistry, University of Turku, FIN-20014 Turku, Finland
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29
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Cofactor-independent oxidases and oxygenases. Appl Microbiol Biotechnol 2010; 86:791-804. [DOI: 10.1007/s00253-010-2455-0] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 01/14/2010] [Accepted: 01/14/2010] [Indexed: 10/19/2022]
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30
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Chipman DM, Barak Z, Shaanan B, Vyazmensky M, Binshtein E, Belenky I, Temam V, Steinmetz A, Golbik R, Tittmann K. Origin of the specificities of acetohydroxyacid synthases and glyoxylate carboligase. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.molcatb.2009.03.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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31
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Ye W, Sangaiah R, Degen DE, Gold A, Jayaraj K, Koshlap KM, Boysen G, Williams J, Tomer KB, Mocanu V, Dicheva N, Parker CE, Schaaper RM, Ball LM. Iminohydantoin lesion induced in DNA by peracids and other epoxidizing oxidants. J Am Chem Soc 2009; 131:6114-23. [PMID: 19354244 DOI: 10.1021/ja8090752] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The oxidation of guanine to 5-carboxamido-5-formamido-2-iminohydantoin (2-Ih) is shown to be a major transformation in the oxidation of the single-stranded DNA 5-mer d(TTGTT) by m-chloroperbenzoic acid (m-CPBA) and dimethyldioxirane (DMDO) as a model for peracid oxidants and in the oxidation of the 5-base pair duplex d[(TTGTT).(AACAA)] with DMDO. 2-Ih has not been reported as an oxidative lesion at the level of single/double-stranded DNA or at the nucleoside/nucleotide level. The lesion is stable to DNA digestion and chromatographic purification, suggesting that 2-Ih may be a stable biomarker in vivo. The oxidation products have been structurally characterized and the reaction mechanism has been probed by oxidation of the monomeric species dGuo, dGMP, and dGTP. DMDO selectively oxidizes the guanine moiety of dGuo, dGMP, and dGTP to 2-Ih, and both peracetic and m-chloroperbenzoic acids exhibit the same selectivity. The presence of the glycosidic bond results in the stereoselective induction of an asymmetric center at the spiro carbon to give a mixture of diastereomers, with each diastereomer in equilibrium with a minor conformer through rotation about the formamido C-N bond. Labeling studies with [(18)O(2)]-m-CPBA and H(2)(18)O to determine the source of the added oxygen atoms have established initial epoxidation of the guanine 4-5 bond with pyrimidine ring contraction by an acyl 1,2-migration of guanine carbonyl C6 to form a transient dehydrodeoxyspiroiminodihydantoin followed by hydrolytic ring-opening of the imidazolone ring. Consistent with the proposed mechanism, no 8-oxoguanine was detected as a product of the oxidations of the oligonucleotides or monomeric species mediated by DMDO or the peracids. The 2-Ih base thus appears to be a pathway-specific lesion generated by peracids and possibly other epoxidizing agents and holds promise as a potential biomarker.
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Affiliation(s)
- Wenjie Ye
- Department of Environmental Sciences and Engineering, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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32
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Wang JG, Lee PKM, Dong YH, Pang SS, Duggleby RG, Li ZM, Guddat LW. Crystal structures of two novel sulfonylurea herbicides in complex with Arabidopsis thaliana acetohydroxyacid synthase. FEBS J 2009; 276:1282-90. [DOI: 10.1111/j.1742-4658.2009.06863.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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33
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Bertoldi M, Cellini B, Montioli R, Borri Voltattorni C. Insights into the mechanism of oxidative deamination catalyzed by DOPA decarboxylase. Biochemistry 2008; 47:7187-95. [PMID: 18547057 DOI: 10.1021/bi800478s] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The unusual oxygen-consuming oxidative deamination reaction catalyzed by the pyridoxal 5'-phosphate (PLP) enzyme DOPA decarboxylase (DDC) was here investigated. Either wild-type or Y332F DDC variant is able to perform such oxidation toward aromatic amines or aromatic l-amino acids, respectively, without the aid of any cofactor related to oxygen chemistry. Oxidative deamination produces, in equivalent amounts, a carbonyl compound and ammonia, accompanied by dioxygen consumption in a 1:2 molar ratio with respect to the products. Kinetic studies either in the pre-steady or in the steady state, together with HPLC analyses of reaction mixtures under varying experimental conditions, revealed that a ketimine accumulates during the linear phase of product formation. This species is reactive since it is converted back to PLP when the substrate is consumed. Rapid-mixing chemical quench studies provide evidence that the ketimine is indeed an intermediate formed during the first catalytic cycle. Moreover, superoxide anion and hydrogen peroxide are both generated during the catalytic cycles. On this basis, a mechanism of oxidative deamination consistent with the present data is proposed. Furthermore, the catalytic properties of the T246A DDC mutant together with those previously obtained with H192Q mutant allow us to propose that the Thr246-His192 dyad could act as a general base in promoting the first step of the oxidative deamination of aromatic amines.
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Affiliation(s)
- Mariarita Bertoldi
- Dipartimento di Scienze Morfologico-Biomediche, sezione di Chimica Biologica, Facoltà di Medicina e Chirurgia, Strada Le Grazie, 8, 37134 Verona, Italy.
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34
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Kluger R, Tittmann K. Thiamin diphosphate catalysis: enzymic and nonenzymic covalent intermediates. Chem Rev 2008; 108:1797-833. [PMID: 18491870 DOI: 10.1021/cr068444m] [Citation(s) in RCA: 216] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ronald Kluger
- Davenport Laboratories, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6 Canada.
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35
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Duggleby RG, McCourt JA, Guddat LW. Structure and mechanism of inhibition of plant acetohydroxyacid synthase. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2008; 46:309-24. [PMID: 18234503 DOI: 10.1016/j.plaphy.2007.12.004] [Citation(s) in RCA: 184] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Indexed: 05/04/2023]
Abstract
Plants and microorganisms synthesize valine, leucine and isoleucine via a common pathway in which the first reaction is catalysed by acetohydroxyacid synthase (AHAS, EC 2.2.1.6). This enzyme is of substantial importance because it is the target of several herbicides, including all members of the popular sulfonylurea and imidazolinone families. However, the emergence of resistant weeds due to mutations that interfere with the inhibition of AHAS is now a worldwide problem. Here we summarize recent ideas on the way in which these herbicides inhibit the enzyme, based on the 3D structure of Arabidopsis thaliana AHAS. This structure also reveals important clues for understanding how various mutations can lead to herbicide resistance.
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Affiliation(s)
- Ronald G Duggleby
- RDBiotech, 22 Parklands Boulevard, Little Mountain, Queensland 4551, Australia.
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36
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37
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Bunik VI, Schloss JV, Pinto JT, Gibson GE, Cooper AJL. Enzyme-Catalyzed Side Reactions with Molecular Oxygen may Contribute to Cell Signaling and Neurodegenerative Diseases. Neurochem Res 2007; 32:871-91. [PMID: 17342415 DOI: 10.1007/s11064-006-9239-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Accepted: 11/22/2006] [Indexed: 02/07/2023]
Abstract
A link between neurodegeneration and well-characterized enzymatic and non-enzymatic reactions that produce reactive oxygen species (ROS) from O(2) is well established. Several enzymes that contain pyridoxal 5'-phosphate (PLP) or thiamine diphosphate (ThDP) catalyze side reactions (paracatalytic reactions) in the presence of ambient O(2). These side reactions produce oxidants such as hydrogen peroxide [H(2)O(2)] or extremely reactive peracids [RC(O)OOH]. We hypothesize that although these enzymes normally produce oxidants at low or undetectable levels, changes in substrate levels or disease-induced structural alterations may enhance interactions with O(2), thereby generating higher levels of reactive oxidants. These oxidants may damage the enzymes producing them, alter nearby macromolecules and/or destroy important metabolites/coenzymes. We propose that paracatalytic reactions with O(2) catalyzed by PLP-dependent decarboxylases and by ThDP-dependent enzymes within the alpha-keto acid dehydrogenase complexes may contribute to normal cellular signaling and to cellular damage in neurodegenerative diseases.
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Affiliation(s)
- Victoria I Bunik
- School of Bioengineering and Bioinformatics, and Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
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38
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Hartman FC, Harpel MR. Chemical and genetic probes of the active site of D-ribulose-1,5-bisphosphate carboxylase/oxygenase: a retrospective based on the three-dimensional structure. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 67:1-75. [PMID: 8322615 DOI: 10.1002/9780470123133.ch1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- F C Hartman
- Biology Division, Oak Ridge National Laboratory, TN
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Kaminaga Y, Schnepp J, Peel G, Kish CM, Ben-Nissan G, Weiss D, Orlova I, Lavie O, Rhodes D, Wood K, Porterfield DM, Cooper AJL, Schloss JV, Pichersky E, Vainstein A, Dudareva N. Plant phenylacetaldehyde synthase is a bifunctional homotetrameric enzyme that catalyzes phenylalanine decarboxylation and oxidation. J Biol Chem 2006; 281:23357-66. [PMID: 16766535 DOI: 10.1074/jbc.m602708200] [Citation(s) in RCA: 185] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have isolated and characterized Petunia hybrida cv. Mitchell phenylacetaldehyde synthase (PAAS), which catalyzes the formation of phenylacetaldehyde, a constituent of floral scent. PAAS is a cytosolic homotetrameric enzyme that belongs to group II pyridoxal 5'-phosphate-dependent amino-acid decarboxylases and shares extensive amino acid identity (approximately 65%) with plant L-tyrosine/3,4-dihydroxy-L-phenylalanine and L-tryptophan decarboxylases. It displays a strict specificity for phenylalanine with an apparent Km of 1.2 mM. PAAS is a bifunctional enzyme that catalyzes the unprecedented efficient coupling of phenylalanine decarboxylation to oxidation, generating phenylacetaldehyde, CO2, ammonia, and hydrogen peroxide in stoichiometric amounts.
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Affiliation(s)
- Yasuhisa Kaminaga
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907-2010, USA
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40
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McCourt JA, Duggleby RG. Acetohydroxyacid synthase and its role in the biosynthetic pathway for branched-chain amino acids. Amino Acids 2006; 31:173-210. [PMID: 16699828 DOI: 10.1007/s00726-005-0297-3] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Accepted: 12/09/2005] [Indexed: 11/25/2022]
Abstract
The branched-chain amino acids are synthesized by plants, fungi and microorganisms, but not by animals. Therefore, the enzymes of this pathway are potential target sites for the development of antifungal agents, antimicrobials and herbicides. Most research has focused upon the first enzyme in this biosynthetic pathway, acetohydroxyacid synthase (AHAS) largely because it is the target site for many commercial herbicides. In this review we provide a brief overview of the important properties of each enzyme within the pathway and a detailed summary of the most recent AHAS research, against the perspective of work that has been carried out over the past 50 years.
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Affiliation(s)
- J A McCourt
- School of Molecular and Microbial Sciences, University of Queensland, Brisbane, Australia
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41
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Abell LM, Hanna WS, Kunitsky KJ, Kerschen JA. Active site inhibitors of acetolactate synthase. ACTA ACUST UNITED AC 2006. [DOI: 10.1002/ps.2780440118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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42
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Vinogradov V, Vyazmensky M, Engel S, Belenky I, Kaplun A, Kryukov O, Barak Z, Chipman DM. Acetohydroxyacid synthase isozyme I from Escherichia coli has unique catalytic and regulatory properties. Biochim Biophys Acta Gen Subj 2006; 1760:356-63. [PMID: 16326011 DOI: 10.1016/j.bbagen.2005.10.008] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Revised: 09/27/2005] [Accepted: 10/20/2005] [Indexed: 11/30/2022]
Abstract
AHAS I is an isozyme of acetohydroxyacid synthase which is apparently unique to enterobacteria. It has been known for over 20 years that it has many properties which are quite different from those of the other two enterobacterial AHASs isozymes, as well as from those of "typical" AHASs which are single enzymes in a given organism. These include a unique mechanism for regulation of expression and the absence of a preference for forming acetohydroxybutyrate. We have cloned the two subunits, ilvB and ilvN, of this Escherichia coli isoenzyme and examined the enzymatic properties of the purified holoenzyme and the enzyme reconstituted from purified subunits. Unlike other AHASs, AHAS I demonstrates cooperative feedback inhibition by valine, and the kinetics fit closely to an exclusive binding model. The formation of acetolactate by AHAS I is readily reversible and acetolactate can act as substrate for alternative AHAS I-catalyzed reactions.
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Affiliation(s)
- Valerie Vinogradov
- Department of Life Sciences, Ben-Gurion University of the Negev, POB 657, Beer-Sheva 84105, Israel
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43
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Bertoldi M, Cellini B, Maras B, Voltattorni CB. A quinonoid is an intermediate of oxidative deamination reaction catalyzed by Dopa decarboxylase. FEBS Lett 2005; 579:5175-80. [PMID: 16150447 DOI: 10.1016/j.febslet.2005.08.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Revised: 08/03/2005] [Accepted: 08/15/2005] [Indexed: 11/20/2022]
Abstract
The reactions of Dopa decarboxylase (DDC) with l- and d-enantiomers of tryptophan methyl ester are described. Although both the enantiomers bind to the active site of the enzyme with similar affinity, their binding modes are different. l-enantiomer binds in an unproductive mode, while d-enantiomer acts as an oxidative deamination substrate. For the first time a quinonoid has been detected as intermediate of this reaction. By using rapid-scanning stopped-flow kinetic technique rate constants for formation and decay of this species have been determined. All these data, besides validating the functional DDC active site model, represent an important step toward the elucidation of the catalytic pathway of oxidative deamination.
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Affiliation(s)
- Mariarita Bertoldi
- Dipartimento di Scienze Neurologiche e della Visione, Sezione di Chimica Biologica, Università di Verona, Italy
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Lee DS, Flachsová E, Bodnárová M, Demeler B, Martásek P, Raman CS. Structural basis of hereditary coproporphyria. Proc Natl Acad Sci U S A 2005; 102:14232-7. [PMID: 16176984 PMCID: PMC1224704 DOI: 10.1073/pnas.0506557102] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2004] [Indexed: 11/18/2022] Open
Abstract
Hereditary coproporphyria is an autosomal dominant disorder resulting from the half-normal activity of coproporphyrinogen oxidase (CPO), a mitochondrial enzyme catalyzing the antepenultimate step in heme biosynthesis. The mechanism by which CPO catalyzes oxidative decarboxylation, in an extraordinary metal- and cofactor-independent manner, is poorly understood. Here, we report the crystal structure of human CPO at 1.58-A resolution. The structure reveals a previously uncharacterized tertiary topology comprising an unusually flat seven-stranded beta-sheet sandwiched by alpha-helices. In the biologically active dimer (K(D) = 5 x 10(-7) M), one monomer rotates relative to the second by approximately 40 degrees to create an intersubunit interface in close proximity to two independent enzymatic sites. The unexpected finding of citrate at the active site allows us to assign Ser-244, His-258, Asn-260, Arg-262, Asp-282, and Arg-332 as residues mediating substrate recognition and decarboxylation. We favor a mechanism in which oxygen serves as the immediate electron acceptor, and a substrate radical or a carbanion with substantial radical character participates in catalysis. Although several mutations in the CPO gene have been described, the molecular basis for how these alterations diminish enzyme activity is unknown. We show that deletion of residues (392-418) encoded by exon six disrupts dimerization. Conversely, harderoporphyria-causing K404E mutation precludes a type I beta-turn from retaining the substrate for the second decarboxylation cycle. Together, these findings resolve several questions regarding CPO catalysis and provide insights into hereditary coproporphyria.
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Affiliation(s)
- Dong-Sun Lee
- Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston, TX 77030, USA
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Abstract
Acetohydroxyacid synthase (Ec 2.2.1.6) catalyses the thiamine diphosphate-dependent reaction between two molecules of pyruvate yielding 2-acetolactacte and CO2. The enzyme will also utilise hydroxypyruvate with a k(cat) value that is 12% of that observed with pyruvate. When hydroxypyruvate is the substrate, the enzyme undergoes progressive inactivation with kinetics that are characteristic of suicide inhibition. It is proposed that the dihydroxyethyl-thiamine diphosphate intermediate can expel a hydroxide ion forming an enol that rearranges to a bound acetyl group.
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Affiliation(s)
- Ronald G Duggleby
- Department of Biochemistry and Molecular Biology, The University of Queensland, Brisbane, Qld 4072, Australia.
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Tittmann K, Vyazmensky M, Hübner G, Barak Z, Chipman DM. The carboligation reaction of acetohydroxyacid synthase II: steady-state intermediate distributions in wild type and mutants by NMR. Proc Natl Acad Sci U S A 2005; 102:553-8. [PMID: 15640355 PMCID: PMC545553 DOI: 10.1073/pnas.0408210101] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The thiamin diphosphate (ThDP)-dependent enzyme acetohydroxyacid synthase (AHAS) catalyzes the first common step in branched-chain amino acid biosynthesis. By specific ligation of pyruvate with the alternative acceptor substrates 2-ketobutyrate and pyruvate, AHAS controls the flux through this branch point and determines the relative rates of synthesis of isoleucine, valine, and leucine, respectively. We used detailed NMR analysis to determine microscopic rate constants for elementary steps in the reactions of AHAS II and mutants altered at conserved residues Arg-276, Trp-464, and Met-250. In Arg276Lys, both the condensation of the enzyme-bound hydroxyethyl-ThDP carbanion/enamine (HEThDP) with the acceptor substrates and acetohydroxyacid release are slowed several orders of magnitude relative to the wild-type enzyme. We propose that the interaction of the guanidinium moiety of Arg-264 with the carboxylate of the acceptor ketoacid provides an optimal alignment of substrate and HEThDP orbitals in the reaction trajectory for acceptor ligation, whereas its interaction with the carboxylate of the covalent HEThDP-acceptor adduct plays a similar role in product release. Both Trp-464 and Met-250 affect the acceptor specificity. The high preference for ketobutyrate in the wild-type enzyme is lost in Trp464Leu as a consequence of similar forward rate constants of carboligation and product release for the alternative acceptors. In Met250Ala, the turnover rate is determined by the condensation of HEThDP with pyruvate and release of the acetolactate product, whereas the parallel steps with 2-ketobutyrate are considerably faster. We speculate that the specificity of carboligation and product liberation may be cumulative if the former is not completely committed.
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Affiliation(s)
- Kai Tittmann
- Department of Life Sciences, Ben-Gurion University of the Negev, 84105 Beer-Sheva, Israel
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Tseng CC, Vaillancourt FH, Bruner SD, Walsh CT. DpgC Is a Metal- and Cofactor-Free 3,5-Dihydroxyphenylacetyl-CoA 1,2-Dioxygenase in the Vancomycin Biosynthetic Pathway. ACTA ACUST UNITED AC 2004; 11:1195-203. [PMID: 15380180 DOI: 10.1016/j.chembiol.2004.06.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Revised: 05/27/2004] [Accepted: 06/09/2004] [Indexed: 11/21/2022]
Abstract
3,5-Dihydroxyphenylglycine is a crucial amino acid monomer in the nonribosomal glycopeptide antibiotic vancomycin. This nonproteinogenic amino acid is constructed from malonyl-CoA by a set of four enzymes, DpgA-D, in the biosynthetic cluster. DpgC is an unusual metal-free, cofactor-free enzyme that consumes O(2) during the conversion of 3,5-dihydroxyphenylacetyl-CoA (DPA-CoA) to the penultimate intermediate 3,5-dihydroxyphenylglyoxylate (DPGx). We show that in anaerobic incubations, DpgC catalyzes the exchange of the C(2)-methylene hydrogens of DPA-CoA at unequal rates, consistent with enzyme-mediated formation of the substrate-derived C(2)-carbanion as an early intermediate. Incubations with (18)O(2) reveal that DpgC transfers both atoms of an O(2) molecule to DPGx product. This establishes DpgC as a 1,2-dioxygenase that mediates thioester cleavage by the oxygen transfer process. These results are consistent with a DPA-CoA C(2)-peroxy intermediate, followed by enzyme-directed alpha-peroxylactone formation and collapse by O-O bond cleavage.
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Affiliation(s)
- Claire C Tseng
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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50
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Biomedical vignette. J Biomed Sci 2001. [DOI: 10.1007/bf02258369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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