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Wang HL, Sun HP, Zheng PR, Cheng RT, Liu ZW, Yuan H, Gao WY, Li H. Re-investigation of in vitro activity of acetohydroxyacid synthase I holoenzyme from Escherichia coli. Arch Biochem Biophys 2024; 754:109962. [PMID: 38499055 DOI: 10.1016/j.abb.2024.109962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 03/14/2024] [Accepted: 03/15/2024] [Indexed: 03/20/2024]
Abstract
Acetohydroxyacid synthase (AHAS) is one of the key enzymes of the biosynthesis of branched-chain amino acids, it is also an effective target for the screening of herbicides and antibiotics. In this study we present a method for preparing Escherichia coli AHAS I holoenzyme (EcAHAS I) with exceptional stability, which provides a solid ground for us to re-investigate the in vitro catalytic properties of the protein. The results show EcAHAS I synthesized in this way exhibits similar function to Bacillus subtilis acetolactate synthase in its catalysis with pyruvate and 2-ketobutyrate (2-KB) as dual-substrate, producing four 2-hydroxy-3-ketoacids including (S)-2-acetolactate, (S)-2-aceto-2-hydroxybutyrate, (S)-2-propionyllactate, and (S)-2-propionyl-2-hydroxybutyrate. Quantification of the reaction indicates that the two substrates almost totally consume, and compound (S)-2-aceto-2- hydroxybutyrate forms in the highest yield among the four major products. Moreover, the protein also condenses two molecules of 2-KB to furnish (S)-2-propionyl-2-hydroxybutyrate. Further exploration manifests that EcAHAS I ligates pyruvate/2-KB and nitrosobenzene to generate two arylhydroxamic acids N-hydroxy-N-phenylacetamide and N-hydroxy-N-phenyl- propionamide. These findings enhance our comprehension of the catalytic characteristics of EcAHAS I. Furthermore, the application of this enzyme as a catalyst in construction of C-N bonds displays promising potential.
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Affiliation(s)
- Hai-Ling Wang
- College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China
| | - Hui-Peng Sun
- College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China
| | - Pei-Rong Zheng
- College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China
| | - Rui-Tong Cheng
- College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China
| | - Zhi-Wen Liu
- College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China
| | - Heng Yuan
- College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China
| | - Wen-Yun Gao
- College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China.
| | - Heng Li
- College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China.
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Egorova OV, Suzina NE, Ilyushina NA. Salmonella mutant strains resistant to herbicides - Acetohydroxyacid synthase inhibitors and their use at the Ames test. Toxicol In Vitro 2023; 93:105699. [PMID: 37751784 DOI: 10.1016/j.tiv.2023.105699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 09/08/2023] [Accepted: 09/22/2023] [Indexed: 09/28/2023]
Abstract
Cytotoxicity of some pesticides is a disadvantage for the Salmonella/microsome assay with regard to the equivalence assessment of pesticide technical grade active ingredients to the original products and detection of low-level impurities. The technical grade active ingredients (TGAIs) of pesticides from certain chemical classes were found to be toxic for Salmonella typhimurium strains. Among the highly cytotoxic compounds were sulfonylureas, which include 20 active ingredients. In addition, this class includes active pharmaceutical ingredients used for the manufacture of antidiabetics drugs. A traditional selection methodology was applied using the cultivation of S. typhimurium TA100 in the presence of high concentrations of thifensulfuronmethyl (TFSM) to obtain a resistant test strain insusceptible to sulfonylurea toxic effect. Two strains resistant not only to sulfonylureas (SFU) but also triazolepyrimidines were received. The first mutant strain (deposited as S. typhimurium VKPM B-14099 in the Russian National Collection of Industrial Microorganisms) demonstrated the TA100 phenotypic characteristics: hisG46, rfa, ΔuvrB-bio, pKM101. The second strain (deposited as S. typhimurium VKPM B-14359) showed the TA1535 phenotypic characteristics and probably lost the R-factor due to the selection using the poor Gm-media with TFSM. Positive controls caused pronounced mutagenic effects (±S9) in both strains, consequently the mutants did not lose the ability to respond to induction of the reverse gene mutations. The maximum non-cytotoxic concentrations of SFUs and triazole-pyrimidines for the Ames test strains did not exceed 0.05-0.125 mg/plate, while no evidence of cytotoxicity was observed for the mutants up to 5.0 mg/plate. Electron microscopy of the ultrathin sections of Salmonella cells grown with and without TFSM showed an obvious difference in the structure of the cell wall and cytoplasm in mutant and parental cultures. The concurrent resistance both to SFU and triazolepyrimidines was assumed to be mediated by the same mechanism of action of the pesticides from these classes - inhibition of acetohydroxyacid synthase. To confirm this hypothesis, the tests in the presence of branched-chain amino acids were carried out. The enrichment of agar with isoleucine prevented the toxic effects of SFU and triazolepyrimidines for all Ames test strains used in the study, while strong cytotoxicity was observed in the presence of valine and leucine. Considering the tolerance of strains both to SFU and triazolpyrimidines and the results with branched-chain amino acids, the modification of target acetohydroxyacid synthase was supposed the key to the acquired resistance. The new strains resistant to sulfonylureas and triazole-pyrimidines expands the possibilities to reveal mutagenic impurities that may occur in TGAIs in small amounts.
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Affiliation(s)
- Olga V Egorova
- Federal Budgetary Establishment of Science «Federal Scientific Center of Hygiene named after F.F.Erisman» of the Federal Service for Surveillance on Consumer Protection and Human Wellbeing, Mytischi 141014, Moscow Region, Russian Federation.
| | - Nataliya E Suzina
- G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Federal Research Center «Pushchino Center for Biological Research of the Russian Academy of Sciences», pr. Nauki, 5, Pushchino, Moscow Region, 142290, Russian Federation
| | - Nataliya A Ilyushina
- Federal Budgetary Establishment of Science «Federal Scientific Center of Hygiene named after F.F.Erisman» of the Federal Service for Surveillance on Consumer Protection and Human Wellbeing, Mytischi 141014, Moscow Region, Russian Federation
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Zhao K, Tang H, Zhang B, Zou S, Liu Z, Zheng Y. Microbial production of vitamin B5: current status and prospects. Crit Rev Biotechnol 2023; 43:1172-1192. [PMID: 36210178 DOI: 10.1080/07388551.2022.2104690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 07/01/2022] [Indexed: 11/03/2022]
Abstract
Vitamin B5, also called D-pantothenic acid (D-PA), is a necessary micronutrient that plays an essential role in maintaining the physiological function of an organism. It is widely used in: food, medicine, feed, cosmetics, and other fields. Currently, the production of D-PA in industry heavily relies on chemical processes and enzymatic catalysis. With an increasing demand on the market, replacing chemical-based production of D-PA with microbial fermentation utilizing renewable resources is necessary. In this review, the physiological role and applications of D-PA were firstly introduced, after which the biosynthesis pathways and enzymes will be summarized. Subsequently, a series of cell factory development strategies for excessive D-PA production are analyzed and discussed. Finally, the prospect of microbial production of D-PA production has been prospected.
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Affiliation(s)
- Kuo Zhao
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, PR China
- College of Biotechnology and Bioengineering, Key Laboratory of Bioorganic Synthesis of Zhejiang Province, Zhejiang University of Technology, Hangzhou, PR China
| | - Heng Tang
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, PR China
- College of Biotechnology and Bioengineering, Key Laboratory of Bioorganic Synthesis of Zhejiang Province, Zhejiang University of Technology, Hangzhou, PR China
| | - Bo Zhang
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, PR China
- College of Biotechnology and Bioengineering, Key Laboratory of Bioorganic Synthesis of Zhejiang Province, Zhejiang University of Technology, Hangzhou, PR China
| | - Shuping Zou
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, PR China
- College of Biotechnology and Bioengineering, Key Laboratory of Bioorganic Synthesis of Zhejiang Province, Zhejiang University of Technology, Hangzhou, PR China
| | - Zhiqiang Liu
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, PR China
- College of Biotechnology and Bioengineering, Key Laboratory of Bioorganic Synthesis of Zhejiang Province, Zhejiang University of Technology, Hangzhou, PR China
| | - Yuguo Zheng
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, PR China
- College of Biotechnology and Bioengineering, Key Laboratory of Bioorganic Synthesis of Zhejiang Province, Zhejiang University of Technology, Hangzhou, PR China
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4
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Hui X, Tian JM, Wang X, Zhang ZQ, Zhao YM, Gao WY, Li H. Overall analyses of the reactions catalyzed by acetohydroxyacid synthase/acetolactate synthase using a precolumn derivatization-HPLC method. Anal Biochem 2023; 660:114980. [PMID: 36368345 DOI: 10.1016/j.ab.2022.114980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 11/01/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022]
Abstract
A precolumn derivatization-HPLC method using 2,4-dinitrophenylhydrazine and 4-nitro-o-phenylenediamine as respective labeling reagents for comprehensive analyses of the reactions catalyzed by acetohydroxyacid synthase (AHAS)/acetolactate synthase (ALS) is developed and evaluated in this research. Comparison with the classic Bauerle' UV assay which can analyze the enzymes only through measurement of acetoin production, the HPLC method shows advantages because it can analyze the enzymes not only via determination of consumption of the substrate pyruvate, but also via measurement of formation of the products including acetoin, 2,3-butanedione, and acetaldehyde in the enzymatic reactions. Thus the results deduced from the HPLC method can reflect the trait of each enzyme in a more precise manner. As far as we know, this is the first time that the reactions mediated by AHAS/ALS using pyruvate as a single substrate are globally analyzed and the features of the enzymes are properly discussed.
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Affiliation(s)
- Xian Hui
- National Engineering Research Center for Miniaturized Detection Systems and College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China
| | - Jin-Meng Tian
- National Engineering Research Center for Miniaturized Detection Systems and College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China
| | - Xin Wang
- National Engineering Research Center for Miniaturized Detection Systems and College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China
| | - Zhen-Qian Zhang
- National Engineering Research Center for Miniaturized Detection Systems and College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China
| | - Ya-Mei Zhao
- National Engineering Research Center for Miniaturized Detection Systems and College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China
| | - Wen-Yun Gao
- National Engineering Research Center for Miniaturized Detection Systems and College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China.
| | - Heng Li
- National Engineering Research Center for Miniaturized Detection Systems and College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, Shaanxi, 710069, China.
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5
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Sel S, Tunç T, Ortaakarsu AB, Mamaş S, Karacan N, Karacan MS. Acetohydroxyacid Synthase (AHAS) Inhibitor‐Based Commercial Sulfonylurea Herbicides as Glutathione Reductase Inhibitors: in Vitro and in Silico Studies. ChemistrySelect 2022. [DOI: 10.1002/slct.202202235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sedat Sel
- İstanbul University Pharmacy Faculty Analytic Chemistry 34116, Beyazıt İstanbul Turkey
| | - Turgay Tunç
- Department of Chemistry Engineering Faculty of Engineering University of Kırşehir Ahi Evran Kırsehir 40100 Turkey
| | | | - Serhat Mamaş
- Gazi University Science Faculty Chemistry Department 06500 Ankara Turkey
| | - Nurcan Karacan
- Gazi University Science Faculty Chemistry Department 06500 Ankara Turkey
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Liang X, Yue Y, Zhao Y, Guo Y, Guo X, Shi B, Yan S. Effects of dietary concentrate to forage ratio on milk performance, milk amino acid composition and milk protein synthesis of lactating donkeys. Anim Feed Sci Technol 2022. [DOI: 10.1016/j.anifeedsci.2022.115444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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7
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Yang X, Huang Q, Xu J, Gao Z, Jiang X, Wu Y, Ye W, Liang Y. Transcriptome reveals BCAAs biosynthesis pathway is influenced by lovastatin and can act as a potential control target in Phytophthora sojae. J Appl Microbiol 2022; 133:3585-3595. [PMID: 36000236 DOI: 10.1111/jam.15792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/16/2022] [Accepted: 08/19/2022] [Indexed: 11/27/2022]
Abstract
AIMS Lovastatin has been indicated to impair growth and development of Phytophthora sojae. Therefore, this study was performed to understand the inhibitory mechanism of lovastatin and investigate the metabolic pathway potentially serviced as a new control target for this plant pathogen. METHODS AND RESULTS Whole transcriptome analysis of lovastatin-treated P. sojae was performed by RNA-sequencing. The results revealed that 84 genes were upregulated and 58 were downregulated with more than four-fold changes under treatment. Kyoto Encyclopedia of Genes and Genomes analysis indicated that the branched-chain amino acids (BCAAs) biosynthesis pathway was abundantly enriched. All enzymes in the BCAAs biosynthesis pathway were identified in the P. sojae genome. Moreover, the study found that the herbicide flumetsulam targeting acetohydroxyacid synthase (AHAS) of the BCAAs biosynthesis pathway could effectively inhibit mycelial growth of P. sojae. CONCLUSIONS Lovastatin treatment significantly influences the BCAAs biosynthesis pathway in P. sojae. Moreover, the herbicide flumetsulam targets AHAS and inhibits growth of P. sojae. SIGNIFICANCE AND IMPACT OF STUDY The present study revealed that BCAAs biosynthesis pathway was influenced by lovastatin treatment and its key enzyme AHAS was identified as a potential new control target, which provides clues for exploring more oomycides to control plant diseases caused by P. sojae.
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Affiliation(s)
- Xinyu Yang
- College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, China
| | - Qifeng Huang
- College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, China
| | - Jitao Xu
- College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, China
| | - Zhen Gao
- College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, China
| | - Xue Jiang
- College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, China
| | - Yuanhua Wu
- College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, China
| | - Wenwu Ye
- College of Plant Protection, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Yue Liang
- College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, China
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8
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Valera A, Wang S, Carr R, Trembleau L, Deng H. Characterization of a class II ketol-acid reductoisomerase from Mycobacterium tuberculosis. RSC Adv 2022; 12:10540-10544. [PMID: 35425013 PMCID: PMC8985424 DOI: 10.1039/d1ra08876a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 03/30/2022] [Indexed: 12/31/2022] Open
Abstract
Mycobacterium tuberculosis ketol-acid reductoisomerases have been widely studied due to their metabolic importance towards development of drug-resistant bacteria treatment. We here report the biochemical characterization of a new KARI (MtKARI-II) from a Mycobacterium tuberculosis variant with a similar kinetic profile to class I KARIs. Phylogenetic analysis suggested that MtKARI-II is clustered into a class II KARI superfamily. Biochemical characterization of an unusual class II KARI (MtKARI-II) from a Mycobacterium tuberculosis variant.![]()
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Affiliation(s)
- Ane Valera
- Department of Chemistry, University of Aberdeen Aberdeen AB24 3UE Scotland UK
| | - Shan Wang
- Department of Chemistry, University of Aberdeen Aberdeen AB24 3UE Scotland UK
| | | | - Laurent Trembleau
- Department of Chemistry, University of Aberdeen Aberdeen AB24 3UE Scotland UK
| | - Hai Deng
- Department of Chemistry, University of Aberdeen Aberdeen AB24 3UE Scotland UK
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Yu S, Zheng B, Chen Z, Huo YX. Metabolic engineering of Corynebacterium glutamicum for producing branched chain amino acids. Microb Cell Fact 2021; 20:230. [PMID: 34952576 PMCID: PMC8709942 DOI: 10.1186/s12934-021-01721-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 12/11/2021] [Indexed: 11/10/2022] Open
Abstract
Background Branched chain amino acids (BCAAs) are widely applied in the food, pharmaceutical, and animal feed industries. Traditional chemical synthetic and enzymatic BCAAs production in vitro has been hampered by expensive raw materials, harsh reaction conditions, and environmental pollution. Microbial metabolic engineering has attracted considerable attention as an alternative method for BCAAs biosynthesis because it is environmentally friendly and delivers high yield. Main text Corynebacterium glutamicum (C. glutamicum) possesses clear genetic background and mature gene manipulation toolbox, and has been utilized as industrial host for producing BCAAs. Acetohydroxy acid synthase (AHAS) is a crucial enzyme in the BCAAs biosynthetic pathway of C. glutamicum, but feedback inhibition is a disadvantage. We therefore reviewed AHAS modifications that relieve feedback inhibition and then investigated the importance of AHAS modifications in regulating production ratios of three BCAAs. We have comprehensively summarized and discussed metabolic engineering strategies to promote BCAAs synthesis in C. glutamicum and offer solutions to the barriers associated with BCAAs biosynthesis. We also considered the future applications of strains that could produce abundant amounts of BCAAs. Conclusions Branched chain amino acids have been synthesized by engineering the metabolism of C. glutamicum. Future investigations should focus on the feedback inhibition and/or transcription attenuation mechanisms of crucial enzymes. Enzymes with substrate specificity should be developed and applied to the production of individual BCAAs. The strategies used to construct strains producing BCAAs provide guidance for the biosynthesis of other high value-added compounds.
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Affiliation(s)
- Shengzhu Yu
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, Beijing, 100081, China
| | - Bo Zheng
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, Beijing, 100081, China
| | - Zhenya Chen
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, Beijing, 100081, China.
| | - Yi-Xin Huo
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Haidian District, Beijing, 100081, China
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AIP1, Encoding the Small Subunit of Acetolactate Synthase, Is Partially Responsible for Resistance to Hypoxic Stress in Arabidopsis thaliana. PLANTS 2021; 10:plants10112251. [PMID: 34834615 PMCID: PMC8621687 DOI: 10.3390/plants10112251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022]
Abstract
Flooding is a significant stress to land plants, depriving them of essential oxygen. Plants have evolved diverse strategies with variable success to survive flooding. Similar strategies have been described in organisms from other kingdoms. Several fungal species can successfully survive a low-oxygen environment by increasing their branched-chain amino acid (BCAA) contents. BCAAs may act as alternative electron acceptors in the respiratory chain under an oxygen-limited environment. The key and first enzyme for BCAA biosynthesis is acetolactate synthase (ALS). We identified two homologous genes encoding the small subunit of ALS in Arabidopsis (Arabidopsis thaliana). We determined that ALS INTERACTING PROTEIN1 (AIP1), which encodes the small subunit of ALS, is strongly expressed in all organs and highly expressed under submergence and low-oxygen stresses. We also showed that the overexpression of AIP1 confers tolerance to low-oxygen stress. These results indicate that ALS may play an essential role under prolonged flooding or oxygen deficiency in Arabidopsis.
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11
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Strengthening the (R)-pantoate pathway to produce D-pantothenic acid based on systematic metabolic analysis. FOOD BIOSCI 2021. [DOI: 10.1016/j.fbio.2021.101283] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Liang YF, Long ZX, Zhang YJ, Luo CY, Yan LT, Gao WY, Li H. The chemical mechanisms of the enzymes in the branched-chain amino acids biosynthetic pathway and their applications. Biochimie 2021; 184:72-87. [PMID: 33607240 DOI: 10.1016/j.biochi.2021.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/04/2021] [Accepted: 02/10/2021] [Indexed: 12/27/2022]
Abstract
l-Valine, l-isoleucine, and l-leucine are three key proteinogenic amino acids, and they are also the essential amino acids required for mammalian growth, possessing important and to some extent, special physiological and biological functions. Because of the branched structures in their carbon chains, they are also named as branched-chain amino acids (BCAAs). This review will highlight the advance in studies of the enzymes involved in the biosynthetic pathway of BCAAs, concentrating on their chemical mechanisms and applications in screening herbicides and antibacterial agents. The uses of some of these enzymes in lab scale organic synthesis are also discussed.
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Affiliation(s)
- Yan-Fei Liang
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China
| | - Zi-Xian Long
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China
| | - Ya-Jian Zhang
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China
| | - Cai-Yun Luo
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China
| | - Le-Tian Yan
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China
| | - Wen-Yun Gao
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China.
| | - Heng Li
- College of Life Sciences, National Engineering Research Center for Miniaturized Detection Systems, Northwest University, Xi'an, 710069, China.
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Ogunade IM, Taiwo G, Estrada-Reyes ZM, Yun J, Pech-Cervantes AA, Peters SO. Effects of a blend of mannan and glucan on growth performance, apparent nutrient digestibility, energy status, and whole-blood immune gene expression of beef steers during a 42-d receiving period. Transl Anim Sci 2021; 5:txaa226. [PMID: 33542996 PMCID: PMC7846145 DOI: 10.1093/tas/txaa226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 12/10/2020] [Indexed: 11/14/2022] Open
Abstract
We examined the effects of dietary supplementation of a blend of mannan and glucan on the growth performance, energy status, and whole-blood immune gene expression of newly weaned beef steers during a 42-d receiving period. Forty-eight newly weaned Angus crossbred steers (2-d post-weaning; 199 ± 13 kg of initial body weight [BW]) from a single source were stratified by BW and randomly assigned to one of the two treatments: basal diet with no additive (CON; n = 24) or a basal diet top-dressed with 5 g of a blend of mannan and glucan (MANGLU; n = 24). Average daily gain (ADG) and feed efficiency (FE) from days 1 to 14, 15 to 42, and 1 to 42 were calculated from daily dry matter intake (DMI) and weekly BW. Blood samples were collected on days 0, 14, and 42 for measurement of plasma glucose and nonesterified fatty acids (NEFA). Blood samples collected on days 14 and 42 were composited for each steer for untargeted carbonyl-metabolome analysis (measurement of carbonyl-containing metabolites). Expression of 84 immune-related genes was analyzed on blood samples collected on day 42. Beginning on days 37 to 42, total mixed ration, refusals, and fecal samples were collected once daily to determine apparent total tract digestibility of DM, CP, NDF, and ADF using indigestible NDF as an internal marker. Over the 42-d feeding trial, supplemental MANGLU tended to increase final BW (P = 0.07) and ADG (P = 0.06). Compared to CON, beef steers fed supplemental MANGLU had greater (P = 0.01) DMI during the first 14 d, greater DM digestibility (P = 0.03), and tended to have greater NDF digestibility (P = 0.09). No treatment effects (P > 0.10) on plasma glucose and NEFA on days 14 and 42 were detected; however, carbonyl-metabolome analysis revealed increased (FDR ≤ 0.05) plasma concentrations of galactose and glyceraldehydes, and altered (FDR ≤ 0.05) concentrations of some microbiome-derived metabolites in beef steers fed MANGLU. Compared with CON, MANGLU increased (P ≤ 0.05) the expression of five immune-related genes involved in recognition of and mounting immune defense against microbial pathogens. In conclusion, the results of this study demonstrated that supplemental MANGLU enhances beef cattle immunocompetence and productivity during feedlot receiving period.
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Affiliation(s)
- Ibukun M Ogunade
- Division of Animal and Nutritional Science, West Virginia University, Morgantown, WV
| | - Godstime Taiwo
- Division of Animal and Nutritional Science, West Virginia University, Morgantown, WV
| | - Zaira M Estrada-Reyes
- College of Agricultural, Family Sciences, and Technology, Fort Valley State University, Fort Valley, GA
| | - Jiang Yun
- Department of Animal Sciences, University of Florida, Gainesville, FL
| | - Andres A Pech-Cervantes
- College of Agricultural, Family Sciences, and Technology, Fort Valley State University, Fort Valley, GA
| | - Sunday O Peters
- Department of Animal Science, Berry College, Mount Berry, GA
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Molecular architecture of the acetohydroxyacid synthase holoenzyme. Biochem J 2020; 477:2439-2449. [DOI: 10.1042/bcj20200292] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/09/2020] [Accepted: 06/11/2020] [Indexed: 01/03/2023]
Abstract
The acetohydroxyacid synthase (AHAS) holoenzyme catalyzes the first step of branch-chain amino acid biosynthesis and is essential for plants and bacteria. It consists of a regulatory subunit (RSU) and a catalytic subunit (CSU). The allosteric mechanism of the AHAS holoenzyme has remained elusive for decades. Here, we determined the crystal structure of the AHAS holoenzyme, revealing the association between the RSU and CSU in an A2B2 mode. Structural analysis in combination with mutational studies demonstrated that the RSU dimer forms extensive interactions with the CSU dimer, in which a conserved salt bridge between R32 and D120 may act as a trigger to open the activation loop of the CSU, resulting in the activation of the CSU by the RSU. Our study reveals the activation mechanism of the AHAS holoenzyme.
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15
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Zhang Y, Liu Y, Zhang S, Ma W, Wang J, Yin L, Wang X. Metabolic engineering of Corynebacterium glutamicum WM001 to improve l-isoleucine production. Biotechnol Appl Biochem 2020; 68:568-584. [PMID: 32474971 DOI: 10.1002/bab.1963] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 05/29/2020] [Indexed: 01/02/2023]
Abstract
In this study, l-isoleucine production in Corynebacterium glutamicum WM001 was improved by deleting three genes in the genome, replacing the native promoter of ilvA in the genome, and overexpression of five genes in an alr-based auxotrophic complementation expression system. The three genes deleted in the genome are alaT, brnQ, and alr. Deletion of alaT improved l-isoleucine production by increasing the supply of pyruvate, whereas deletion of brnQ improved l-isoleucine production by blocking the uptake of extracellular l-isoleucine. Exchange of the native promoter of ilvA with promoter tac or tacM could contribute to l-isoleucine production by increasing 2-ketobutyric acid; tac is better than tacM for improving l-isoleucine yield. Different combinations of the genes ilvBN, ppnK, lrp, and brnFE were overexpressed in an alr-based auxotrophic complementation expression system to further improve l-isoleucine production, and the best yield after 72-H flask fermentation was obtained from the strain WM005/pYCW-1-ilvBN2-ppnK1. Without addition of any antibiotics, WM005/pYCW-1-ilvBN2-ppnK1 could produce 32.1 g/L l-isoleucine after 72-H fed-batch fermentation, which is 34.3% increase compared with the original strain WM001.
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Affiliation(s)
- Yanchao Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China
| | - Yadi Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China
| | - Shuyan Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China
| | - Wenjian Ma
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China
| | - Jianli Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, People's Republic of China
| | - Lianghong Yin
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, People's Republic of China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, People's Republic of China.,State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, People's Republic of China.,International Joint Laboratory on Food Safety, Jiangnan University, Wuxi, People's Republic of China
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16
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Amemiya K, Dankmeyer JL, Biryukov SS, Treviño SR, Klimko CP, Mou SM, Fetterer DP, Garnes PG, Cote CK, Worsham PL, DeShazer D. Deletion of Two Genes in Burkholderia pseudomallei MSHR668 That Target Essential Amino Acids Protect Acutely Infected BALB/c Mice and Promote Long Term Survival. Vaccines (Basel) 2019; 7:vaccines7040196. [PMID: 31779073 PMCID: PMC6963190 DOI: 10.3390/vaccines7040196] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/31/2019] [Accepted: 11/15/2019] [Indexed: 12/25/2022] Open
Abstract
Melioidosis is an emerging disease that is caused by the facultative intracellular pathogen Burkholderia pseudomallei. It is intrinsically resistant to many antibiotics and host risk factors play a major role in susceptibility to infection. Currently, there is no human or animal vaccine against melioidosis. In this study, multiple B. pseudomallei MSHR668 deletion mutants were evaluated as live attenuated vaccines in the sensitive BALB/c mouse model of melioidosis. The most efficacious vaccines after an intraperitoneal challenge with 50-fold over the 50% median lethal dose (MLD50) with B. pseudomallei K96243 were 668 ΔhisF and 668 ΔilvI. Both vaccines completely protected mice in the acute phase of infection and showed significant protection (50% survivors) during the chronic phase of infection. The spleens of the survivors that were examined were sterile. Splenocytes from mice vaccinated with 668 ΔhisF and 668 ΔilvI expressed higher amounts of IFN-γ after stimulation with B. pseudomallei antigens than splenocytes from mice vaccinated with less protective candidates. Finally, we demonstrate that 668 ΔhisF is nonlethal in immunocompromised NOD/SCID mice. Our results show that 668 ΔhisF and 668 ΔilvI provide protective cell-mediated immune responses in the acute phase of infection and promote long term survival in the sensitive BALB/c mouse model of melioidosis.
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Affiliation(s)
- Kei Amemiya
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - Jennifer L. Dankmeyer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - Sergei S. Biryukov
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - Sylvia R. Treviño
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - Christopher P. Klimko
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - Sherry M. Mou
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - David P. Fetterer
- Biostatistical Services, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (D.P.F.); (P.G.G.)
| | - Preston G. Garnes
- Biostatistical Services, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (D.P.F.); (P.G.G.)
| | - Christopher K. Cote
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - Patricia L. Worsham
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
| | - David DeShazer
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (K.A.); (J.L.D.); (S.S.B.); (S.R.T.); (C.P.K.); (S.M.M.); (C.K.C.); (P.L.W.)
- Correspondence: ; Tel.: +1-301-619-4919
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17
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Xie Y, Zhang C, Wang Z, Wei C, Liao N, Wen X, Niu C, Yi L, Wang Z, Xi Z. Fluorogenic Assay for Acetohydroxyacid Synthase: Design and Applications. Anal Chem 2019; 91:13582-13590. [PMID: 31603309 DOI: 10.1021/acs.analchem.9b02739] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Acetohydroxyacid synthase (AHAS) exists in plants and many microorganisms (including gut flora) but not in mammals, making it an attractive drug target. Fluorescent-based methods should be practical for high-throughput screening of inhibitors. Herein, we describe the development of the first AHAS fluorogenic assay based on an intramolecular charge transfer (ICT)-based fluorescent probe. The assay is facile, sensitive, and continuous and can be applied toward various AHASs from different species, AHAS mutants, and crude cell lysates. The fluorogenic assay was successfully applied for (1) high-throughput screening of commerical herbicides toward different AHASs for choosing matching herbicides, (2) identification of a Soybean AHAS gene with broad-spectrum herbicide resistance, and (3) identification of selective inhibitors toward intestinal-bacterial AHASs. Among the AHAS inhibitors, an active agent was found for selective inhibition of obesity-associated Ruminococcus torques growth, implying the possibility of AHAS inhibitors for the ultimate goal toward antiobesity therapeutics. The fluorogenic assay opens the door for high-throughput programs in AHAS-related fields, and the design principle might be applied for development of fluorogenic assays of other synthases.
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Affiliation(s)
- Yonghui Xie
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, National Pesticide Engineering Research Center (Tianjin), College of Chemistry , Nankai University , Tianjin 300071 , P. R. China
| | - Changyu Zhang
- State Key Laboratory of Organic-Inorganic Composites and Beijing Key Lab of Bioprocess , Beijing University of Chemical Technology (BUCT) , Beijing 100029 , P. R. China
| | - Zhihua Wang
- State Key Laboratory of Bioreactor Engineering , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , P. R. China
| | - Chao Wei
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, National Pesticide Engineering Research Center (Tianjin), College of Chemistry , Nankai University , Tianjin 300071 , P. R. China
| | - Ningjing Liao
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, National Pesticide Engineering Research Center (Tianjin), College of Chemistry , Nankai University , Tianjin 300071 , P. R. China
| | - Xin Wen
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, National Pesticide Engineering Research Center (Tianjin), College of Chemistry , Nankai University , Tianjin 300071 , P. R. China
| | - Congwei Niu
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, National Pesticide Engineering Research Center (Tianjin), College of Chemistry , Nankai University , Tianjin 300071 , P. R. China
| | - Long Yi
- State Key Laboratory of Organic-Inorganic Composites and Beijing Key Lab of Bioprocess , Beijing University of Chemical Technology (BUCT) , Beijing 100029 , P. R. China.,Collaborative Innovation Center of Chemical Science and Engineering , Nankai University , Tianjin 300071 , P. R. China
| | - Zejian Wang
- State Key Laboratory of Bioreactor Engineering , East China University of Science and Technology , 130 Meilong Road , Shanghai 200237 , P. R. China
| | - Zhen Xi
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, National Pesticide Engineering Research Center (Tianjin), College of Chemistry , Nankai University , Tianjin 300071 , P. R. China.,Collaborative Innovation Center of Chemical Science and Engineering , Nankai University , Tianjin 300071 , P. R. China
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18
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Deb SS, Reshamwala SMS, Lali AM. Activation of alternative metabolic pathways diverts carbon flux away from isobutanol formation in an engineered Escherichia coli strain. Biotechnol Lett 2019; 41:823-836. [PMID: 31093837 DOI: 10.1007/s10529-019-02683-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Accepted: 05/02/2019] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Metabolic engineering efforts are guided by identifying gene targets for overexpression and/or deletion. Isobutanol, a biofuel candidate, is biosynthesized using the valine biosynthesis pathway and enzymes of the Ehrlich pathway. Most reported studies for isobutanol production in Escherichia coli employ multicopy plasmids, an approach that suffers from disadvantages such as plasmid instability, increased metabolic burden, and use of antibiotics to maintain selection pressure. Cofactor imbalance is another issue that may limit production of isobutanol, as two enzymes of the pathway utilize NADPH as a cofactor. RESULTS To address these issues, we constructed E. coli strains with chromosomally-integrated, codon-optimized isobutanol pathway genes (ilvGM, ilvC, kivd, adh) selected on the basis of their cofactor preferences. Genes involved in diverting pyruvate flux toward fermentation byproducts were deleted. Metabolite analyses of the constructed strains revealed extracellular accumulation of significant amounts of isobutyraldehyde, a pathway intermediate, and the overflow metabolites 2,3-butanediol and acetol. CONCLUSIONS These results demonstrate that the genetic modifications carried out led to activation of alternative pathways that diverted carbon flux toward formation of unwanted metabolites. The present study highlights how precursor metabolites can be metabolized through enzymatic routes that have not been considered important in previous studies due to the different strategies employed therein. The insights gained from the present study will allow rational genetic modification of host cells for production of metabolites of interest.
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Affiliation(s)
- Shalini S Deb
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Nathatlal Parekh Marg, Matunga (East), Mumbai, Maharashtra, 400019, India
| | - Shamlan M S Reshamwala
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Nathatlal Parekh Marg, Matunga (East), Mumbai, Maharashtra, 400019, India.
| | - Arvind M Lali
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Nathatlal Parekh Marg, Matunga (East), Mumbai, Maharashtra, 400019, India
- Department of Chemical Engineering, Institute of Chemical Technology, Nathatlal Parekh Marg, Matunga (East), Mumbai, Maharashtra, 400019, India
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19
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Xie Y, Wen X, Zhao D, Niu C, Zhao Y, Qi H, Xi Z. Interactions between the ACT Domains and Catalytic Subunits of Acetohydroxyacid Synthases (AHASs) from Different Species. Chembiochem 2018; 19:2387-2394. [DOI: 10.1002/cbic.201800367] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/16/2018] [Indexed: 01/05/2023]
Affiliation(s)
- Yonghui Xie
- State Key Laboratory of Elemento-Organic Chemistry; Department of Chemical Biology; National Pesticide Engineering Research Center (Tianjin); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); College of Chemistry; Nankai University; Tianjin 300071 P.R. China
| | - Xin Wen
- State Key Laboratory of Elemento-Organic Chemistry; Department of Chemical Biology; National Pesticide Engineering Research Center (Tianjin); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); College of Chemistry; Nankai University; Tianjin 300071 P.R. China
| | - Dongmei Zhao
- State Key Laboratory of Elemento-Organic Chemistry; Department of Chemical Biology; National Pesticide Engineering Research Center (Tianjin); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); College of Chemistry; Nankai University; Tianjin 300071 P.R. China
| | - Congwei Niu
- State Key Laboratory of Elemento-Organic Chemistry; Department of Chemical Biology; National Pesticide Engineering Research Center (Tianjin); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); College of Chemistry; Nankai University; Tianjin 300071 P.R. China
| | - Yuefang Zhao
- State Key Laboratory of Elemento-Organic Chemistry; Department of Chemical Biology; National Pesticide Engineering Research Center (Tianjin); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); College of Chemistry; Nankai University; Tianjin 300071 P.R. China
| | - Haoman Qi
- State Key Laboratory of Elemento-Organic Chemistry; Department of Chemical Biology; National Pesticide Engineering Research Center (Tianjin); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); College of Chemistry; Nankai University; Tianjin 300071 P.R. China
| | - Zhen Xi
- State Key Laboratory of Elemento-Organic Chemistry; Department of Chemical Biology; National Pesticide Engineering Research Center (Tianjin); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin); College of Chemistry; Nankai University; Tianjin 300071 P.R. China
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20
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Wang X, Zhang H, Quinn PJ. Production of l-valine from metabolically engineered Corynebacterium glutamicum. Appl Microbiol Biotechnol 2018; 102:4319-4330. [DOI: 10.1007/s00253-018-8952-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/15/2018] [Accepted: 03/16/2018] [Indexed: 01/25/2023]
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21
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Su L, Lv M, Kyeremeh K, Deng Z, Deng H, Yu Y. A ThDP-dependent enzymatic carboligation reaction involved in Neocarazostatin A tricyclic carbazole formation. Org Biomol Chem 2018; 14:8679-8684. [PMID: 27714211 DOI: 10.1039/c6ob01651k] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Although the biosynthetic pathway of Neocarazostatin A (1) has been identified, the detailed enzymatic reactions underlying the assembly of the carbazole ring still remain largely unknown. We demonstrate here that NzsH, a putative thiamine diphosphate dependent enzyme, can catalyze an acyloin coupling reaction between indole-3-pyruvate and pyruvate to generate a β-ketoacid intermediate. Our findings thus shed light on further characterization of the unusual biosynthetic pathway of the bacterial tricyclic carbazole alkaloids.
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Affiliation(s)
- Li Su
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan 430071, P.R. China.
| | - Meinan Lv
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan 430071, P.R. China.
| | - Kwaku Kyeremeh
- Department of Chemistry, University of Ghana, P.O. Box LG56, Legon-Accra, Ghana
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan 430071, P.R. China.
| | - Hai Deng
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, Scotland, UK
| | - Yi Yu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University, 185 East Lake Road, Wuhan 430071, P.R. China.
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22
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Jia X, Liu Y, Han Y. A thermophilic cell-free cascade enzymatic reaction for acetoin synthesis from pyruvate. Sci Rep 2017; 7:4333. [PMID: 28659601 PMCID: PMC5489476 DOI: 10.1038/s41598-017-04684-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 05/18/2017] [Indexed: 11/09/2022] Open
Abstract
Acetoin (3-hydroxy-2-butanone) is an important bio-based platform chemical with wide applications. In vitro enzyme catalysed synthesis exhibits great feasibility in the production of chemicals with high purity. In the present work, a synthetic pathway involving a two-step continuous reaction was constructed in vitro for acetoin production from pyruvate at improved temperature. Thermostable candidates, acetolactate synthase (coAHASL1 and coAHASL2 from Caldicellulosiruptor owensensis OL) and α-acetolactate decarboxylase (bsALDC from Bacillus subtilis IPE5-4) were cloned, heterologously expressed, and characterized. All the enzymes showed maximum activities at 65–70 °C and pH of 6.5. Enzyme kinetics analysis showed that coAHASL1 had a higher activity but lower affinity against pyruvate than that of coAHASL2. In addition, the activities of coAHASL1 and bsALDC were promoted by Mn2+ and NADPH. The cascade enzymatic reaction was optimized by using coAHASL1 and bsALDC based on their kinetic properties. Under optimal conditions, a maximum concentration of 3.36 ± 0.26 mM acetoin was produced from 10 mM pyruvate after reaction for 24 h at 65 °C. The productivity of acetoin was 0.14 mM h−1, and the yield was 67.80% compared with the theoretical value. The results confirmed the feasibility of synthesis of acetoin from pyruvate with a cell-free enzyme catalysed system at improved temperature.
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Affiliation(s)
- Xiaojing Jia
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China.,University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Ying Liu
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China
| | - Yejun Han
- National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, PR China.
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23
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Li H, Liu N, Hui X, Gao WY. An improved enzymatic method for the preparation of (R)-phenylacetyl carbinol. RSC Adv 2017. [DOI: 10.1039/c7ra04641c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
(R)-Phenylacetyl carbinol (R-PAC) is one of the key chiral α-hydroxyketones utilized as a synthon in the synthesis of a number of pharmaceuticals having α- and β-adrenergic properties.
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Affiliation(s)
- Heng Li
- National Engineering Research Center for Miniaturized Detection Systems
- College of Life Sciences
- Northwest University
- Xi'an
- China
| | - Nan Liu
- Department of Experimental Surgery
- Tangdu Hospital
- Fourth Military Medical University
- Xi'an
- China
| | - Xian Hui
- National Engineering Research Center for Miniaturized Detection Systems
- College of Life Sciences
- Northwest University
- Xi'an
- China
| | - Wen-Yun Gao
- National Engineering Research Center for Miniaturized Detection Systems
- College of Life Sciences
- Northwest University
- Xi'an
- China
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24
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Abstract
Organophosphonic acids are unique as natural products in terms of stability and mimicry. The C-P bond that defines these compounds resists hydrolytic cleavage, while the phosphonyl group is a versatile mimic of transition-states, intermediates, and primary metabolites. This versatility may explain why a variety of organisms have extensively explored the use organophosphonic acids as bioactive secondary metabolites. Several of these compounds, such as fosfomycin and bialaphos, figure prominently in human health and agriculture. The enzyme reactions that create these molecules are an interesting mix of chemistry that has been adopted from primary metabolism as well as those with no chemical precedent. Additionally, the phosphonate moiety represents a source of inorganic phosphate to microorganisms that live in environments that lack this nutrient; thus, unusual enzyme reactions have also evolved to cleave the C-P bond. This review is a comprehensive summary of the occurrence and function of organophosphonic acids natural products along with the mechanisms of the enzymes that synthesize and catabolize these molecules.
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Affiliation(s)
- Geoff P Horsman
- Department of Chemistry and Biochemistry, Wilfrid Laurier University , Waterloo, Ontario N2L 3C5, Canada
| | - David L Zechel
- Department of Chemistry, Queen's University , Kingston, Ontario K7L 3N6, Canada
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25
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Liu Y, Li Y, Wang X. Acetohydroxyacid synthases: evolution, structure, and function. Appl Microbiol Biotechnol 2016; 100:8633-49. [DOI: 10.1007/s00253-016-7809-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 07/28/2016] [Accepted: 08/12/2016] [Indexed: 10/21/2022]
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26
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Lloyd Evans D, Joshi SV. Elucidating modes of activation and herbicide resistance by sequence assembly and molecular modelling of the Acetolactate synthase complex in sugarcane. J Theor Biol 2016; 407:184-197. [PMID: 27452529 DOI: 10.1016/j.jtbi.2016.07.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 06/14/2016] [Accepted: 07/20/2016] [Indexed: 10/21/2022]
Abstract
Acetolactate synthase (ALS) catalyzes the first portion of the biosynthetic pathway leading to the generation of branched-chain amino acids. As such it is essential for plant health and is a major target for herbicides. ALS is a very poorly characterized molecule in sugarcane. The enzyme is activated and inhibited by a regulatory subunit (known as VAT1 in plants) whose mode of action is entirely unknown. Using Saccharum halepense as a template we have assembled the ALS gene of sugarcane (Saccharum hybrid) and have modelled the structure of ALS based on an Arabidopsis template (the first ALS model for a monocot). We have also assembled the ALS regulatory proteins (VAT1 and VAT2) from sugarcane and show that VAT2 is specific to true grasses. Employing a bacterial model, we have generated a structural model for VAT1, which explains why the separate domains of the proteins bind to either leucine or valine but not both. Using co-evolution studies we have determined molecular contacts by which we modelled the docking of VAT1 to ALS. In conclusion, we demonstrate how the binding of VAT1 to ALS activates ALS and show how VAT1 can also confer feedback inhibition to ALS. We validate our ALS model against biochemical data and employ this model to explain the function of a novel herbicide binding mutant in sugarcane.
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Affiliation(s)
- Dyfed Lloyd Evans
- South African Sugarcane Research Institute, 170 Flanders Drive, Private Bag X02, Mount Edgecombe, Durban 4300, South Africa; School of Life Sciences, College of Agriculture, Engineering and Science, University of Kwa-Zulu Natal, Private Bag X54001, Durban 4000, South Africa.
| | - Shailesh Vinay Joshi
- South African Sugarcane Research Institute, 170 Flanders Drive, Private Bag X02, Mount Edgecombe, Durban 4300, South Africa; School of Life Sciences, College of Agriculture, Engineering and Science, University of Kwa-Zulu Natal, Private Bag X54001, Durban 4000, South Africa
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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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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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Eram MS, Sarafuddin B, Gong F, Ma K. Characterization of acetohydroxyacid synthase from the hyperthermophilic bacterium Thermotoga maritima. Biochem Biophys Rep 2015; 4:89-97. [PMID: 29124191 PMCID: PMC5668897 DOI: 10.1016/j.bbrep.2015.08.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 08/24/2015] [Accepted: 08/24/2015] [Indexed: 11/30/2022] Open
Abstract
Acetohydroxyacid synthase (AHAS) is the key enzyme in branched chain amino acid biosynthesis pathway. The enzyme activity and properties of a highly thermostable AHAS from the hyperthermophilic bacterium Thermotoga maritima is being reported. The catalytic and regulatory subunits of AHAS from T. maritima were over-expressed in Escherichia coli. The recombinant subunits were purified using a simplified procedure including a heat-treatment step followed by chromatography. A discontinuous colorimetric assay method was optimized and used to determine the kinetic parameters. AHAS activity was determined to be present in several Thermotogales including T. maritima. The catalytic subunit of T. maritima AHAS was purified approximately 30-fold, with an AHAS activity of approximately 160±27 U/mg and native molecular mass of 156±6 kDa. The regulatory subunit was purified to homogeneity and showed no catalytic activity as expected. The optimum pH and temperature for AHAS activity were 7.0 and 85 °C, respectively. The apparent Km and Vmax for pyruvate were 16.4±2 mM and 246±7 U/mg, respectively. Reconstitution of the catalytic and regulatory subunits led to increased AHAS activity. This is the first report on characterization of an isoleucine, leucine, and valine operon (ilv operon) enzyme from a hyperthermophilic microorganism and may contribute to our understanding of the physiological pathways in Thermotogales. The enzyme represents the most active and thermostable AHAS reported so far. First report of AHAS from a hyperthermophilic bacterium. Catalytic and regulatory subunits of AHAS of T. maritima was expressed in E. coli. Recombinant proteins were purified using a simplified procedure. Enzyme represents the most active and thermostable AHAS reported so far. Kinetic parameters were determined for the purified recombinant enzyme
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Key Words
- AHAS, acetohydroxyacid synthase
- Acetohydroxyacid synthase
- BCAA, branched chain amino acid
- Branched-chain amino acids
- CCE, crude cell extract
- CFE, cell-free extract
- HTCCE, heat-treated crude cell extract
- Hyperthermophiles
- IB, inclusion body
- IMAC, immobilized metal affinity chromatography
- TPP, thiamine pyrophosphate
- Thermotogales
- TmAHAS, Thermotoga maritima acetohydroxyacid synthase
- ilv, isoleucine, leucine, valine
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Affiliation(s)
- Mohammad S Eram
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Benozir Sarafuddin
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Frank Gong
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Kesen Ma
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
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Sommer B, von Moeller H, Haack M, Qoura F, Langner C, Bourenkov G, Garbe D, Loll B, Brück T. Detailed structure-function correlations of Bacillus subtilis acetolactate synthase. Chembiochem 2014; 16:110-8. [PMID: 25393087 DOI: 10.1002/cbic.201402541] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Indexed: 02/04/2023]
Abstract
Isobutanol is deemed to be a next-generation biofuel and a renewable platform chemical.1 Non-natural biosynthetic pathways for isobutanol production have been implemented in cell-based and in vitro systems with Bacillus subtilis acetolactate synthase (AlsS) as key biocatalyst.2-6 AlsS catalyzes the condensation of two pyruvate molecules to acetolactate with thiamine diphosphate and Mg(2+) as cofactors. AlsS also catalyzes the conversion of 2-ketoisovalerate into isobutyraldehyde, the immediate precursor of isobutanol. Our phylogenetic analysis suggests that the ALS enzyme family forms a distinct subgroup of ThDP-dependent enzymes. To unravel catalytically relevant structure-function relationships, we solved the AlsS crystal structure at 2.3 Å in the presence of ThDP, Mg(2+) and in a transition state with a 2-lactyl moiety bound to ThDP. We supplemented our structural data by point mutations in the active site to identify catalytically important residues.
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Affiliation(s)
- Bettina Sommer
- Fachgebiet Industrielle Biokatalyse, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching (Germany)
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Argôlo Santos Carvalho H, de Andrade Silva EM, Carvalho Santos S, Micheli F. Polygalacturonases from Moniliophthora perniciosa are regulated by fermentable carbon sources and possible post-translational modifications. Fungal Genet Biol 2013; 60:110-21. [DOI: 10.1016/j.fgb.2013.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 09/30/2013] [Accepted: 10/06/2013] [Indexed: 11/30/2022]
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Bunik VI, Tylicki A, Lukashev NV. Thiamin diphosphate-dependent enzymes: from enzymology to metabolic regulation, drug design and disease models. FEBS J 2013; 280:6412-42. [PMID: 24004353 DOI: 10.1111/febs.12512] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 07/29/2013] [Accepted: 08/21/2013] [Indexed: 02/06/2023]
Abstract
Bringing a knowledge of enzymology into research in vivo and in situ is of great importance in understanding systems biology and metabolic regulation. The central metabolic significance of thiamin (vitamin B1 ) and its diphosphorylated derivative (thiamin diphosphate; ThDP), and the fundamental differences in the ThDP-dependent enzymes of metabolic networks in mammals versus plants, fungi and bacteria, or in health versus disease, suggest that these enzymes are promising targets for biotechnological and medical applications. Here, the in vivo action of known regulators of ThDP-dependent enzymes, such as synthetic structural analogs of the enzyme substrates and thiamin, is analyzed in light of the enzymological data accumulated during half a century of research. Mimicking the enzyme-specific catalytic intermediates, the phosphonate analogs of 2-oxo acids selectively inhibit particular ThDP-dependent enzymes. Because of their selectivity, use of these compounds in cellular and animal models of ThDP-dependent enzyme malfunctions improves the validity of the model and its predictive power when compared with the nonselective and enzymatically less characterized oxythiamin and pyrithiamin. In vitro studies of the interaction of thiamin analogs and their biological derivatives with potential in vivo targets are necessary to identify and attenuate the analog selectivity. For both the substrate and thiamin synthetic analogs, in vitro reactivities with potential targets are highly relevant in vivo. However, effective concentrations in vivo are often higher than in vitro studies would suggest. The significance of specific inihibition of the ThDP-dependent enzymes for the development of herbicides, antibiotics, anticancer and neuroprotective strategies is discussed.
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Affiliation(s)
- Victoria I Bunik
- A.N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, Moscow, Russia; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
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Baig IA, Gedi V, Lee SC, Koh SH, Yoon MY. Role of a highly conserved proline-126 in ThDP binding of Mycobacterium tuberculosis acetohydroxyacid synthase. Enzyme Microb Technol 2013; 53:243-9. [PMID: 23931689 DOI: 10.1016/j.enzmictec.2013.05.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 05/12/2013] [Accepted: 05/14/2013] [Indexed: 11/30/2022]
Abstract
Acetohydroxyacid synthase (AHAS) of Mycobacterium tuberculosis is a promising target for the development of anti-tuberculosis agents. With the absence of an available bacterial AHAS crystal structure, that of M. tuberculosis, site-directed mutagenesis has been a useful tool for determining its structural and functional features. In this study, a highly conserved proline residue (P126 of M. tuberculosis AHAS) was selected, and the possible role was evaluated by site-directed mutagenesis. P126 was replaced by valine, threonine, alanine, and glutamate to yield P126V, P126T, P126A, and P126E, respectively. All variants were expressed in their soluble forms in Escherichia coli and purified to near homogeneity. The molecular mass (SDS-PAGE) of the purified variants was ∼68 kDa, which is similar to that of wild-type AHAS. The P126V, P126T, and P126A variants exhibited significantly lower activity than wild-type AHAS, whereas P126E was inactive under the tested assay conditions. Furthermore, the P126V and P126T variants showed a significantly decreased preference toward pyruvate and ThDP as substrate and cofactor respectively, whereas the P126A showed similar kinetics to that of wild-type AHAS. Like in AHAS from yeast Saccharomyces cerevisiae (PDB ID: 1N0H), residue P126 is located in the ThDP binding pocket of M. tuberculosis AHAS homology model. Collectively, these results suggest that the conserved P126 plays a significant role in the ThDP binding of M. tuberculosis AHAS.
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Lee MY, Lee SC, Cho JH, Ryu SE, Koo BS, Yoon MY. Role of a Highly Conserved and Catalytically Important Glutamate-49 in the Enterococcus faecalis Acetolactate Synthase. B KOREAN CHEM SOC 2013. [DOI: 10.5012/bkcs.2013.34.2.669] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Chien PN, Jung IP, Reddy KV, Yoon MY. Mechanism Studies of Substituted Triazol-1-yl-pyrimidine Derivatives Inhibition on Mycobacterium tuberculosis Acetohydroxyacid Synthase. B KOREAN CHEM SOC 2012. [DOI: 10.5012/bkcs.2012.33.12.4074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Zhao Y, Wen X, Niu C, Xi Z. Arginine 26 and Aspartic Acid 69 of the Regulatory Subunit are Key Residues of Subunits Interaction of Acetohydroxyacid Synthase Isozyme III fromE. coli. Chembiochem 2012; 13:2445-54. [DOI: 10.1002/cbic.201200362] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Indexed: 11/08/2022]
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