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Unconventional biochemical regulation of the oxidative pentose phosphate pathway in the model cyanobacterium Synechocystis sp. PCC 6803. Biochem J 2020; 477:1309-1321. [PMID: 32227111 DOI: 10.1042/bcj20200038] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/11/2020] [Accepted: 03/30/2020] [Indexed: 01/05/2023]
Abstract
Metabolite production from carbon dioxide using sugar catabolism in cyanobacteria has been in the spotlight recently. Synechocystis sp. PCC 6803 (Synechocystis 6803) is the most studied cyanobacterium for metabolite production. Previous in vivo analyses revealed that the oxidative pentose phosphate (OPP) pathway is at the core of sugar catabolism in Synechocystis 6803. However, the biochemical regulation of the OPP pathway enzymes in Synechocystis 6803 remains unknown. Therefore, we characterized a key enzyme of the OPP pathway, glucose-6-phosphate dehydrogenase (G6PDH), and related enzymes from Synechocystis 6803. Synechocystis 6803 G6PDH was inhibited by citrate in the oxidative tricarboxylic acid (TCA) cycle. Citrate has not been reported as an inhibitor of G6PDH before. Similarly, 6-phosphogluconate dehydrogenase, the other enzyme from Synechocystis 6803 that catalyzes the NADPH-generating reaction in the OPP pathway, was inhibited by citrate. To understand the physiological significance of this inhibition, we characterized succinic semialdehyde dehydrogenase (SSADH) from Synechocystis 6803 (SySSADH), which catalyzes one of the NAD(P)H generating reactions in the oxidative TCA cycle. Similar to isocitrate dehydrogenase from Synechocystis 6803, SySSADH specifically catalyzed the NADPH-generating reaction and was not inhibited by citrate. The activity of SySSADH was lower than that of other bacterial SSADHs. Previous and this studies revealed that unlike the OPP pathway, the oxidative TCA cycle is a pathway with low efficiency in NADPH generation in Synechocystis 6803. It has, thus, been suggested that to avoid NADPH overproduction, the OPP pathway dehydrogenase activity is repressed when the flow of the oxidative TCA cycle increases in Synechocystis 6803.
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2
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Xie C, Li ZM, Bai F, Hu Z, Zhang W, Li Z. Kinetic and structural insights into enzymatic mechanism of succinic semialdehyde dehydrogenase from Cyanothece sp. ATCC51142. PLoS One 2020; 15:e0239372. [PMID: 32966327 PMCID: PMC7510979 DOI: 10.1371/journal.pone.0239372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 09/06/2020] [Indexed: 11/26/2022] Open
Abstract
As a ubiquitous enzyme, succinic semialdehyde dehydrogenase contributes significantly in many pathways including the tricarboxylic acid cycle and other metabolic processes such as detoxifying the accumulated succinic semialdehyde and surviving in nutrient-limiting conditions. Here the cce4228 gene encoding succinic semialdehyde dehydrogenase from Cyanothece sp. ATCC51142 was cloned and the homogenous recombinant cce4228 protein was obtained by Ni-NTA affinity chromatography. Biochemical characterization revealed that cce4228 protein displayed optimal activity at presence of metal ions in basic condition. Although the binding affinity of cce4228 protein with NAD+ was about 50-fold lower than that of cce4228 with NADP+, the catalytic efficiency of cce4228 protein towards succinic semialdehyde with saturated concentration of NADP+ is same as that with saturated concentration of NAD+ as its cofactors. Meanwhile, the catalytic activity of cce4228 was competitively inhibited by succinic semialdehyde substrate. Kinetic and structural analysis demonstrated that the conserved Cys262 and Glu228 residues were crucial for the catalytic activity of cce4228 protein and the Ser157 and Lys154 residues were determinants of cofactor preference.
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Affiliation(s)
- Congcong Xie
- College of Bioscience and Bioengineering, Jiangxi Key Laboratory for Conservation and Utilization of Fungal Resources, Jiangxi Agricultural University, Nanchang, Jiangxi, China
| | - Zhi-Min Li
- College of Science, Jiangxi Agricultural University, Nanchang, Jiangxi, China
| | - Fumei Bai
- College of Bioscience and Bioengineering, Jiangxi Key Laboratory for Conservation and Utilization of Fungal Resources, Jiangxi Agricultural University, Nanchang, Jiangxi, China
| | - Ziwei Hu
- College of Bioscience and Bioengineering, Jiangxi Key Laboratory for Conservation and Utilization of Fungal Resources, Jiangxi Agricultural University, Nanchang, Jiangxi, China
| | - Wei Zhang
- College of Bioscience and Bioengineering, Jiangxi Key Laboratory for Conservation and Utilization of Fungal Resources, Jiangxi Agricultural University, Nanchang, Jiangxi, China
| | - Zhimin Li
- College of Bioscience and Bioengineering, Jiangxi Key Laboratory for Conservation and Utilization of Fungal Resources, Jiangxi Agricultural University, Nanchang, Jiangxi, China
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3
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Muñoz-Clares RA, Casanova-Figueroa K. The importance of assessing aldehyde substrate inhibition for the correct determination of kinetic parameters and mechanisms: the case of the ALDH enzymes. Chem Biol Interact 2019; 305:86-97. [PMID: 30928398 DOI: 10.1016/j.cbi.2019.03.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/23/2019] [Accepted: 03/25/2019] [Indexed: 01/22/2023]
Abstract
Substrate inhibition by the aldehyde has been observed for decades in NAD(P)+-dependent aldehyde dehydrogenase (ALDH) enzymes, which follow a Bi Bi ordered steady-state kinetic mechanism. In this work, by using theoretical simulations of different possible substrate inhibition mechanisms in monosubstrate and Bi Bi ordered steady-state reactions, we explored the kind and extent of errors arising when estimating the kinetic parameters and determining the kinetic mechanisms if substrate inhibition is intentionally or unintentionally ignored. We found that, in every mechanism, fitting the initial velocity data of apparently non-inhibitory substrate concentrations to a rectangular hyperbola produces important errors, not only in the estimation of Vmax values, which were underestimated as expected, but, surprisingly, even more in the estimation of Km values, which led to overestimation of the Vmax/Km values. We show that the greater errors in Km arises from fitting data that do experience substrate inhibition, although it may not be evident, to a Michaelis-Menten equation, which causes overestimation of the data at low substrate concentrations. Similarly, we show that if substrate inhibition is not fully assessed when inhibitors are evaluated, the estimated inhibition constants will have significant errors, and the type of inhibition could be grossly mistaken. We exemplify these errors with experimental results obtained with the betaine aldehyde dehydrogenase from spinach showing the errors predicted by the theoretical simulations and that these errors are increased in the presence of NADH, which in this enzyme favors aldehyde substrate inhibition. Therefore, we strongly recommend assessing substrate inhibition by the aldehyde in every ALDH kinetic study, particularly when inhibitors are evaluated. The common practices of using an apparently non-inhibitory concentration range of the aldehyde or a single high concentration of the aldehyde or the coenzyme when varying the other to determine true kinetic parameters should be abandoned.
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Affiliation(s)
- Rosario A Muñoz-Clares
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México, 04510, Mexico.
| | - Karla Casanova-Figueroa
- Departamento de Bioquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México, 04510, Mexico
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4
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Phonbuppha J, Maenpuen S, Munkajohnpong P, Chaiyen P, Tinikul R. Selective determination of the catalytic cysteine pK a of two-cysteine succinic semialdehyde dehydrogenase from Acinetobacter baumannii using burst kinetics and enzyme adduct formation. FEBS J 2018; 285:2504-2519. [PMID: 29734522 DOI: 10.1111/febs.14497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 03/27/2018] [Accepted: 04/30/2018] [Indexed: 11/27/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH) from Acinetobacter baumannii (Ab) catalyzes the oxidation of succinic semialdehyde (SSA). This enzyme has two conserved cysteines (Cys289 and Cys291) and preferentially uses NADP+ over NAD+ as a hydride acceptor. Steady-state kinetic analysis showed that AbSSADH has the highest catalytic turnover (137 s-1 ) and can tolerate SSA inhibition the most (< 500 μm) among all SSADHs reported. Alanine substitutions of the two conserved cysteines indicated that Cys291Ala has ~ 65% activity compared with the wild-type enzyme while Cys289Ala is inactive, suggesting that Cys289 is the active residue participating in catalysis. Pre-steady-state kinetics showed for the first time burst kinetics for NADPH formation in SSADH, indicating that the rate-limiting step is associated with steps that occur after the hydride transfer. As the magnitude of burst kinetics represents the amount of NADPH formed during the first turnover, it is directly dependent on the amount of the deprotonated form of cysteine. The pKa of Cys289 was calculated from a plot of the burst magnitude vs pH as 7.4 ± 0.2. The Cys289 pKa was also measured based on the ability of AbSSADH to form an NADP-cysteine adduct, which can be detected by the increase of absorbance at ~ 330 nm as 7.9 ± 0.2. The lowering of the catalytic cysteine pKa by 0.6-1 unit renders the catalytic thiol more nucleophilic, which facilitates AbSSADH catalysis under physiological conditions. The methods established herein can specifically measure the active site cysteine pKa without interference from other cysteines. These techniques may be useful for studying ionization state of other cysteine-containing aldehyde dehydrogenases. ENZYME Succinic semialdehyde dehydrogenase, EC1.2.1.24.
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Affiliation(s)
- Jittima Phonbuppha
- Department of Biomolecular Science and Engineering, School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.,Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Somchart Maenpuen
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi, Thailand
| | - Pobthum Munkajohnpong
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Pimchai Chaiyen
- Department of Biomolecular Science and Engineering, School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.,Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Ruchanok Tinikul
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand.,Mahidol University, Nakhonsawan, Thailand
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5
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γ-Aminobutyric Acid (GABA): Biosynthesis, Role, Commercial Production, and Applications. STUDIES IN NATURAL PRODUCTS CHEMISTRY 2018. [DOI: 10.1016/b978-0-444-64057-4.00013-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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6
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Wang X, Lai C, Lei G, Wang F, Long H, Wu X, Chen J, Huo G, Li Z. Kinetic characterization and structural modeling of an NADP +-dependent succinic semialdehyde dehydrogenase from Anabaena sp. PCC7120. Int J Biol Macromol 2017; 108:615-624. [PMID: 29242124 DOI: 10.1016/j.ijbiomac.2017.12.059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 12/07/2017] [Accepted: 12/08/2017] [Indexed: 11/16/2022]
Abstract
Succinic semialdehyde dehydrogenases (SSADH) of cyanobacteria played a pivotal role in completing the cyanobacterial tricarboxylic acid cycle. The structural information of cofactor preference and catalysis for SSADH from cyanobacteria is currently available. However, the detailed kinetics of SSADH from cyanobacteria were not characterized yet. In this study, an all3556 gene encoding SSADH from Anabaena sp. PCC7120 (ApSSADH) was amplified and the recombinant ApSSADH was purified homogenously. Kinetic analysis showed that ApSSADH was an NADP+-dependent SSADH, which utilized NADP+ and succinic semialdehyde (SSA) as its preferred substrates and the activity of ApSSADH was inhibited by its substrate of SSA. At the same time, the Ser157 residue was found to function as the determinant of cofactor preference. Further study demonstrated that activity and substrate inhibition of ApSSADH would be greatly reduced by the mutation of the residues at the active site. Bioinformatic analysis indicated that those residues were highly conserved throughout the SSADHs. To our knowledge this is the first report exploring the detailed kinetics of SSADH from cyanobacteria.
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Affiliation(s)
- Xiaoqin Wang
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China
| | - Chongde Lai
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; Collaborative Innovation Center of Postharvest Key Technology and Quality Safety of Fruits and Vegetables in Jiangxi Province, Nanchang 330045, China
| | - Guofeng Lei
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China
| | - Fei Wang
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; Collaborative Innovation Center of Postharvest Key Technology and Quality Safety of Fruits and Vegetables in Jiangxi Province, Nanchang 330045, China; Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Jiangxi Agricultural University, Nanchang 330045, China.
| | - Haozhi Long
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; Jiangxi Key Laboratory for Conservation and Utilization of Fungal Resources, Jiangxi Agricultural University, Nanchang 330045, China
| | - Xiaoyu Wu
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; Collaborative Innovation Center of Postharvest Key Technology and Quality Safety of Fruits and Vegetables in Jiangxi Province, Nanchang 330045, China; Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Jiangxi Agricultural University, Nanchang 330045, China
| | - Jinyin Chen
- Collaborative Innovation Center of Postharvest Key Technology and Quality Safety of Fruits and Vegetables in Jiangxi Province, Nanchang 330045, China
| | - Guanghua Huo
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; Jiangxi Key Laboratory for Conservation and Utilization of Fungal Resources, Jiangxi Agricultural University, Nanchang 330045, China
| | - Zhimin Li
- College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang 330045, China; Collaborative Innovation Center of Postharvest Key Technology and Quality Safety of Fruits and Vegetables in Jiangxi Province, Nanchang 330045, China; Jiangxi Engineering Laboratory for the Development and Utilization of Agricultural Microbial Resources, Jiangxi Agricultural University, Nanchang 330045, China; Jiangxi Key Laboratory for Conservation and Utilization of Fungal Resources, Jiangxi Agricultural University, Nanchang 330045, China.
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7
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Metabolic pathway of 6-aminohexanoate in the nylon oligomer-degrading bacterium Arthrobacter sp. KI72: identification of the enzymes responsible for the conversion of 6-aminohexanoate to adipate. Appl Microbiol Biotechnol 2017; 102:801-814. [DOI: 10.1007/s00253-017-8657-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 11/11/2017] [Accepted: 11/13/2017] [Indexed: 10/18/2022]
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8
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Metabolic plasticity of central carbon metabolism protects mycobacteria. Proc Natl Acad Sci U S A 2015; 112:13135-6. [PMID: 26483480 DOI: 10.1073/pnas.1518171112] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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9
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E1 of α-ketoglutarate dehydrogenase defends Mycobacterium tuberculosis against glutamate anaplerosis and nitroxidative stress. Proc Natl Acad Sci U S A 2015; 112:E5834-43. [PMID: 26430237 DOI: 10.1073/pnas.1510932112] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Enzymes of central carbon metabolism (CCM) in Mycobacterium tuberculosis (Mtb) make an important contribution to the pathogen's virulence. Evidence is emerging that some of these enzymes are not simply playing the metabolic roles for which they are annotated, but can protect the pathogen via additional functions. Here, we found that deficiency of 2-hydroxy-3-oxoadipate synthase (HOAS), the E1 component of the α-ketoglutarate (α-KG) dehydrogenase complex (KDHC), did not lead to general metabolic perturbation or growth impairment of Mtb, but only to the specific inability to cope with glutamate anaplerosis and nitroxidative stress. In the former role, HOAS acts to prevent accumulation of aldehydes, including growth-inhibitory succinate semialdehyde (SSA). In the latter role, HOAS can participate in an alternative four-component peroxidase system, HOAS/dihydrolipoyl acetyl transferase (DlaT)/alkylhydroperoxide reductase colorless subunit gene (ahpC)-neighboring subunit (AhpD)/AhpC, using α-KG as a previously undescribed source of electrons for reductase action. Thus, instead of a canonical role in CCM, the E1 component of Mtb's KDHC serves key roles in situational defense that contribute to its requirement for virulence in the host. We also show that pyruvate decarboxylase (AceE), the E1 component of pyruvate dehydrogenase (PDHC), can participate in AceE/DlaT/AhpD/AhpC, using pyruvate as a source of electrons for reductase action. Identification of these systems leads us to suggest that Mtb can recruit components of its CCM for reactive nitrogen defense using central carbon metabolites.
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10
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Structural insight into the substrate inhibition mechanism of NADP(+)-dependent succinic semialdehyde dehydrogenase from Streptococcus pyogenes. Biochem Biophys Res Commun 2015; 461:487-93. [PMID: 25888791 DOI: 10.1016/j.bbrc.2015.04.047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 04/07/2015] [Indexed: 11/21/2022]
Abstract
Succinic semialdehyde dehydrogenases (SSADHs) are ubiquitous enzymes that catalyze the oxidation of succinic semialdehyde (SSA) to succinic acid in the presence of NAD(P)(+), and play an important role in the cellular mechanisms including the detoxification of accumulated SSA or the survival in conditions of limited nutrients. Here, we report the inhibitory properties and two crystal structures of SSADH from Streptococcus pyogenes (SpSSADH) in a binary (ES) complex with SSA as the substrate and a ternary (ESS) complex with the substrate SSA and the inhibitory SSA, at 2.4 Å resolution for both structures. Analysis of the kinetic inhibitory parameters revealed significant substrate inhibition in the presence of NADP(+) at concentrations of SSA higher than 0.02 mM, which exhibited complete uncompetitive substrate inhibition with the inhibition constant (Ki) value of 0.10 ± 0.02 mM. In ES-complex of SpSSADH, the SSA showed a tightly bound bent form nearby the catalytic residues, which may be caused by reduction of the cavity volume for substrate binding, compared with other SSADHs. Moreover, structural comparison of ESS-complex with a binary complex with NADP(+) of SpSSADH indicated that the substrate inhibition was induced by the binding of inhibitory SSA in the cofactor-binding site, instead of NADP(+). Our results provide first structure-based molecular insights into the substrate inhibition mechanism of SpSSADH as the Gram-positive bacterial SSADH.
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11
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Zhang J, Liu Y. A QM/MM study of the catalytic mechanism of succinic semialdehyde dehydrogenase from Synechococcus sp. PCC 7002 and Salmonella typhimurium. RSC Adv 2015. [DOI: 10.1039/c5ra21535h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The catalytic mechanism of succinic semialdehyde dehydrogenase (SSADH) has been studied using a combined quantum mechanics and molecular mechanics (QM/MM) approach.
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Affiliation(s)
- Jing Zhang
- Key Laboratory of Colloid and Interface Chemistry
- Ministry of Education
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan
| | - Yongjun Liu
- Key Laboratory of Colloid and Interface Chemistry
- Ministry of Education
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan
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12
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Jang EH, Ah Park S, Min Chi Y, Lee KS. Kinetic and structural characterization for cofactor preference of succinic semialdehyde dehydrogenase from Streptococcus pyogenes. Mol Cells 2014; 37:719-26. [PMID: 25256219 PMCID: PMC4213762 DOI: 10.14348/molcells.2014.0162] [Citation(s) in RCA: 9] [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: 06/10/2014] [Revised: 08/29/2014] [Accepted: 09/02/2014] [Indexed: 02/04/2023] Open
Abstract
The γ-Aminobutyric acid (GABA) that is found in prokaryotic and eukaryotic organisms has been used in various ways as a signaling molecule or a significant component generating metabolic energy under conditions of nutrient limitation or stress, through GABA catabolism. Succinic semialdehyde dehydrogenase (SSADH) catalyzes the oxidation of succinic semialdehyde to succinic acid in the final step of GABA catabolism. Here, we report the catalytic properties and two crystal structures of SSADH from Streptococcus pyogenes (SpSSADH) regarding its cofactor preference. Kinetic analysis showed that SpSSADH prefers NADP(+) over NAD(+) as a hydride acceptor. Moreover, the structures of SpSSADH were determined in an apo-form and in a binary complex with NADP(+) at 1.6 Å and 2.1 Å resolutions, respectively. Both structures of SpSSADH showed dimeric conformation, containing a single cysteine residue in the catalytic loop of each subunit. Further structural analysis and sequence comparison of SpSSADH with other SSADHs revealed that Ser158 and Tyr188 in SpSSADH participate in the stabilization of the 2'-phosphate group of adenine-side ribose in NADP(+). Our results provide structural insights into the cofactor preference of SpSSADH as the gram-positive bacterial SSADH.
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Affiliation(s)
- Eun Hyuk Jang
- Department of Biosystems and Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713,
Korea
| | - Seong Ah Park
- Department of Clinical Laboratory Science, College of Health Sciences, Catholic University of Pusan, Busan 609-757,
Korea
| | - Young Min Chi
- Department of Biosystems and Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713,
Korea
| | - Ki Seog Lee
- Department of Clinical Laboratory Science, College of Health Sciences, Catholic University of Pusan, Busan 609-757,
Korea
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13
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Park J, Rhee S. Structural basis for a cofactor-dependent oxidation protection and catalysis of cyanobacterial succinic semialdehyde dehydrogenase. J Biol Chem 2013; 288:15760-70. [PMID: 23589281 DOI: 10.1074/jbc.m113.460428] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Succinic semialdehyde dehydrogenase (SSADH) from cyanobacterium Synechococcus differs from other SSADHs in the γ-aminobutyrate shunt. Synechococcus SSADH (SySSADH) is a TCA cycle enzyme and completes a 2-oxoglutarate dehydrogenase-deficient cyanobacterial TCA cycle through a detour metabolic pathway. SySSADH produces succinate in an NADP(+)-dependent manner with a single cysteine acting as the catalytic residue in the catalytic loop. Crystal structures of SySSADH were determined in their apo form, as a binary complex with NADP(+) and as a ternary complex with succinic semialdehyde and NADPH, providing details about the catalytic mechanism by revealing a covalent adduct of a cofactor with the catalytic cysteine in the binary complex and a proposed thiohemiacetal intermediate in the ternary complex. Further analyses showed that SySSADH is an oxidation-sensitive enzyme and that the formation of the NADP-cysteine adduct is a kinetically preferred event that protects the catalytic cysteine from H2O2-dependent oxidative stress. These structural and functional features of SySSADH provide a molecular basis for cofactor-dependent oxidation protection in 1-Cys SSADH, which is unique relative to other 2-Cys SSADHs employing a redox-dependent formation of a disulfide bridge.
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Affiliation(s)
- Jinseo Park
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
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14
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Zheng H, Beliavsky A, Tchigvintsev A, Brunzelle JS, Brown G, Flick R, Evdokimova E, Wawrzak Z, Mahadevan R, Anderson WF, Savchenko A, Yakunin AF. Structure and activity of the NAD(P)+-dependent succinate semialdehyde dehydrogenase YneI from Salmonella typhimurium. Proteins 2013; 81:1031-41. [PMID: 23229889 DOI: 10.1002/prot.24227] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 11/18/2012] [Indexed: 01/25/2023]
Abstract
Aldehyde dehydrogenases are found in all organisms and play an important role in the metabolic conversion and detoxification of endogenous and exogenous aldehydes. Genomes of many organisms including Escherichia coli and Salmonella typhimurium encode two succinate semialdehyde dehydrogenases with low sequence similarity and different cofactor preference (YneI and GabD). Here, we present the crystal structure and biochemical characterization of the NAD(P)(+)-dependent succinate semialdehyde dehydrogenase YneI from S. typhimurium. This enzyme shows high activity and affinity toward succinate semialdehyde and exhibits substrate inhibition at concentrations of SSA higher than 0.1 mM. YneI can use both NAD(+) and NADP(+) as cofactors, although affinity to NAD(+) is 10 times higher. High resolution crystal structures of YneI were solved in a free state (1.85 Å) and in complex with NAD(+) (1.90 Å) revealing a two domain protein with the active site located in the interdomain interface. The NAD(+) molecule is bound in the long channel with its nicotinamide ring positioned close to the side chain of the catalytic Cys268. Site-directed mutagenesis demonstrated that this residue, as well as the conserved Trp136, Glu365, and Asp426 are important for activity of YneI, and that the conserved Lys160 contributes to the enzyme preference to NAD(+) . Our work has provided further insight into the molecular mechanisms of substrate selectivity and activity of succinate semialdehyde dehydrogenases.
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Affiliation(s)
- Hongyan Zheng
- Department of Chemical Engineering and Applied Chemistry, Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada
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15
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Yuan Z, Yin B, Wei D, Yuan YRA. Structural basis for cofactor and substrate selection by cyanobacterium succinic semialdehyde dehydrogenase. J Struct Biol 2013; 182:125-35. [PMID: 23500184 DOI: 10.1016/j.jsb.2013.03.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/28/2013] [Accepted: 03/03/2013] [Indexed: 10/27/2022]
Abstract
Aldehyde dehydrogenase (ALDH) catalyzes the oxidation of aldehydes to carboxylic acids. Cyanobacterium Synechococcus contains one ALDH enzyme (Sp2771), together with a novel 2-oxoglutarate decarboxylase, to complete a non-canonical tricarboxylic acid cycle. However, the molecular mechanisms for substrate selection and cofactor preference by Sp2771 are largely unknown. Here, we report crystal structures of wild type Sp2771, Sp2771 S419A mutant and ternary structure of Sp2771 C262A mutant in complex with NADP(+) and SSA, as well as binary structure of Gluconobacter oxydans aldehyde dehydrogenase (Gox0499) in complex with PEG. Structural comparison of Sp2771 with Gox0499, coupled with mutational analysis, demonstrates that Ser157 residue in Sp2771 and corresponding Pro159 residue in Gox0499 play critical structural roles in determining NADP(+) and NAD(+) preference for Sp2771 and Gox0499, respectively, whereas size and distribution of hydrophobic residues along the substrate binding funnel determine substrate selection. Hence, our work has provided insightful structural information into cofactor and substrate selection by ALDH.
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Affiliation(s)
- Zuanning Yuan
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
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16
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Quartararo CE, Hazra S, Hadi T, Blanchard JS. Structural, kinetic and chemical mechanism of isocitrate dehydrogenase-1 from Mycobacterium tuberculosis. Biochemistry 2013; 52:1765-75. [PMID: 23409873 PMCID: PMC3706558 DOI: 10.1021/bi400037w] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Mycobacterium tuberculosis (Mtb) is the leading cause of death due to a bacterial infection. The success of the Mtb pathogen has largely been attributed to the nonreplicating, persistence phase of the life cycle, for which the glyoxylate shunt is required. In Escherichia coli, flux through the shunt is controlled by regulation of isocitrate dehydrogenase (ICDH). In Mtb, the mechanism of regulation is unknown, and currently, there is no mechanistic or structural information about ICDH. We optimized expression and purification to a yield sufficiently high to perform the first detailed kinetic and structural studies of Mtb ICDH-1. A large solvent kinetic isotope effect [(D2O)V = 3.0 ± 0.2, and (D2O)(V/Kisocitrate) = 1.5 ± 0.3] and a smaller primary kinetic isotope effect [(D)V = 1.3 ± 0.1, and (D)(V/K[2R-(2)H]isocitrate) = 1.5 ± 0.2] allowed us to perform the first multiple kinetic isotope effect studies on any ICDH and suggest a chemical mechanism. In this mechanism, protonation of the enolate to form product α-ketoglutarate is the rate-limiting step. We report the first structure of Mtb ICDH-1 to 2.18 Å by X-ray crystallography with NADPH and Mn(2+) bound. It is a homodimer in which each subunit has a Rossmann fold, and a common top domain of interlocking β sheets. Mtb ICDH-1 is most structurally similar to the R132H mutant human ICDH found in glioblastomas. Similar to human R132H ICDH, Mtb ICDH-1 also catalyzes the formation of α-hydroxyglutarate. Our data suggest that regulation of Mtb ICDH-1 is novel.
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Affiliation(s)
- Christine E. Quartararo
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461
| | - Saugata Hazra
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461
| | - Timin Hadi
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461
| | - John S. Blanchard
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461.,To whom correspondence should be addressed: Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461. Phone: (718) 430-3096. Fax: (718) 430-8565.
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Functional γ-Aminobutyrate Shunt in Listeria monocytogenes: role in acid tolerance and succinate biosynthesis. Appl Environ Microbiol 2012; 79:74-80. [PMID: 23064337 DOI: 10.1128/aem.02184-12] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Listeria monocytogenes, the causative agent of human listeriosis, is known for its ability to withstand severe environmental stresses. The glutamate decarboxylase (GAD) system is one of the principal systems utilized by the bacterium to cope with acid stress, a reaction that produces γ-aminobutyrate (GABA) from glutamate. Recently, we have shown that GABA can accumulate intracellularly under acidic conditions, even under conditions where no extracellular glutamate-GABA exchange is detectable. The GABA shunt, a pathway that metabolizes GABA to succinate, has been described for several other bacterial genera, and the present study sought to determine whether L. monocytogenes has this metabolic capacity, which, if present, could provide a possible route for succinate biosynthesis in L. monocytogenes. Using crude protein extracts from L. monocytogenes EGD-e, we show that this strain exhibits activity for the two main enzyme reactions in the GABA shunt, GABA aminotransferase (GABA-AT) and succinic semialdehyde dehydrogenase (SSDH). Two genes were identified as candidates for encoding these enzyme activities, argD (GABA-AT) and lmo0913 (SSDH). Crude protein extracts prepared from a mutant lacking a functional argD gene significantly reduced GABA-AT activity, while an lmo0913 mutant lost all detectable SSDH activity. The deletion of lmo0913 increased the acid tolerance of EGD-e and showed an increased accumulation of intracellular GABA, suggesting that this pathway plays a significant role in the survival of this pathogen under acidic conditions. This is the first report of such a pathway in the genus Listeria, which highlights an important link between metabolism and acid tolerance and also presents a possible compensatory pathway to partially overcome the incomplete tricarboxylic acid cycle of Listeria.
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Feehily C, Karatzas KAG. Role of glutamate metabolism in bacterial responses towards acid and other stresses. J Appl Microbiol 2012; 114:11-24. [PMID: 22924898 DOI: 10.1111/j.1365-2672.2012.05434.x] [Citation(s) in RCA: 242] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 08/15/2012] [Accepted: 08/16/2012] [Indexed: 12/13/2022]
Abstract
Glutamate plays a central role in a wide range of metabolic processes in bacterial cells. This review focuses on the involvement of glutamate in bacterial stress responses. In particular, it reviews the role of glutamate metabolism in response against acid stress and other stresses. The glutamate decarboxylase (GAD) system has been implicated in acid tolerance in several bacterial genera. This system facilitates intracellular pH homoeostasis by consuming protons in a decarboxylation reaction that produces γ-aminobutyrate (GABA) from glutamate. An antiporter system is usually present to couple the uptake of glutamate to the efflux of GABA. Recent insights into the functioning of this system will be discussed. Finally, the intracellular fate of GABA will also be discussed. Many bacteria are capable of metabolizing GABA to succinate via the GABA shunt pathway. The role and regulation of this pathway will be addressed in the review.
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Affiliation(s)
- C Feehily
- Bacterial Stress Response Group, Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
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Jang EH, Lim JE, Chi YM, Lee KS. Crystallization and preliminary X-ray crystallographic studies of succinic semialdehyde dehydrogenase from Streptococcus pyogenes. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:288-91. [PMID: 22442224 DOI: 10.1107/s1744309111052055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 12/02/2011] [Indexed: 12/27/2022]
Abstract
Succinic semialdehyde dehydrogenase (SSADH) plays a critical role in the metabolism of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) and catalyzes the NAD(P)(+)-coupled oxidation of succinic semialdehyde (SSA) to succinic acid (SA). SSADH from Streptococcus pyogenes has been purified and crystallized as the apoenzyme and in a complex with NAD(+). The crystals of native and NAD(+)-complexed SSADH diffracted to resolutions of 1.6 and 1.7 Å, respectively, using a synchrotron-radiation source. Both crystals belonged to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 93.3, b = 100.3, c = 105.1 Å for the native crystal and a = 93.3, b = 100.3, c = 105.0 Å for the complex crystal. Preliminary molecular replacement confirmed the presence of one dimer in both crystals, corresponding to a Matthews coefficient (V(M)) of 2.37 Å(3) Da(-1) and a solvent content of 48.0%.
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Affiliation(s)
- Eun Hyuk Jang
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713, Republic of Korea
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Identification and characterization of γ-aminobutyric acid uptake system GabPCg (NCgl0464) in Corynebacterium glutamicum. Appl Environ Microbiol 2012; 78:2596-601. [PMID: 22307305 DOI: 10.1128/aem.07406-11] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Corynebacterium glutamicum is widely used for industrial production of various amino acids and vitamins, and there is growing interest in engineering this bacterium for more commercial bioproducts such as γ-aminobutyric acid (GABA). In this study, a C. glutamicum GABA-specific transporter (GabP(Cg)) encoded by ncgl0464 was identified and characterized. GabP(Cg) plays a major role in GABA uptake and is essential to C. glutamicum growing on GABA. GABA uptake by GabP(Cg) was weakly competed by l-Asn and l-Gln and stimulated by sodium ion (Na(+)). The K(m) and V(max) values were determined to be 41.1 ± 4.5 μM and 36.8 ± 2.6 nmol min(-1) (mg dry weight [DW])(-1), respectively, at pH 6.5 and 34.2 ± 1.1 μM and 67.3 ± 1.0 nmol min(-1) (mg DW)(-1), respectively, at pH 7.5. GabP(Cg) has 29% amino acid sequence identity to a previously and functionally identified aromatic amino acid transporter (TyrP) of Escherichia coli but low identities to the currently known GABA transporters (17% and 15% to E. coli GabP and Bacillus subtilis GabP, respectively). The mutant RES167 Δncgl0464/pGXKZ9 with the GabP(Cg) deletion showed 12.5% higher productivity of GABA than RES167/pGXKZ9. It is concluded that GabP(Cg) represents a new type of GABA transporter and is potentially important for engineering GABA-producing C. glutamicum strains.
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