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Du Z, Gao F, Wang S, Sun S, Chen C, Wang X, Wu R, Yu X. Genome-Wide Investigation of Oxidosqualene Cyclase Genes Deciphers the Genetic Basis of Triterpene Biosynthesis in Tea Plants. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:10584-10595. [PMID: 38652774 DOI: 10.1021/acs.jafc.4c00346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Triterpenoids from Camellia species comprise a diverse class of bioactive compounds with great therapeutic potential. However, triterpene biosynthesis in tea plants (Camellia sinensis) remains elusive. Here, we identified eight putative 2,3-oxidosqualene cyclase (OSC) genes (CsOSC1-8) from the tea genome and characterized the functions of five through heterologous expression in yeast and tobacco and transient overexpression in tea plants. CsOSC1 was found to be a β-amyrin synthase, whereas CsOSC4, 5, and 6 exhibited multifunctional α-amyrin synthase activity. Molecular docking and site-directed mutagenesis showed that the CsOSC6M259T/W260L double mutant yielded >40% lupeol, while the CsOSC1 W259L single mutant alone was sufficient for lupeol production. The V732F mutation in CsOSC5 altered product formation from friedelin to taraxasterol and ψ-taraxasterol. The L254 M mutation in the cycloartenol synthase CsOSC8 enhanced the catalytic activity. Our findings shed light on the molecular basis governing triterpene diversity in tea plants and offer potential avenues for OSC engineering.
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Affiliation(s)
- Zhenghua Du
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Center for Plant Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Fuquan Gao
- Center for Plant Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shuyan Wang
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shuai Sun
- College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Chanxin Chen
- School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xiaxia Wang
- Center for Plant Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ruimei Wu
- Center for Plant Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Xiaomin Yu
- Center for Plant Metabolomics, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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Guo H, Chen T, Zhu H, Wang H, Huo YX. Engineering amino acid residues of pentacyclic triterpene synthases for improving the activity. Appl Microbiol Biotechnol 2024; 108:195. [PMID: 38324205 PMCID: PMC10850208 DOI: 10.1007/s00253-024-13030-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 09/10/2023] [Accepted: 01/25/2024] [Indexed: 02/08/2024]
Abstract
Pentacyclic triterpenoids exhibit a wide range of biological activities which have wide applications in the food, cosmetics, and pharmaceutical industries. High-performance chassis strains have been developed for the production of various pentacyclic triterpenoids, e.g., lupane-type and oleanane-type triterpenoids. The production of common pentacyclic triterpenes and their derivatives is limited by the poor activity of typical pentacyclic triterpene synthases (PTSs). However, a general strategy applicable to typical PTSs is still lacking. As typical pentacyclic triterpenes are derived from the baccharenyl cation, engineering the non-active-site residues in the MXXXXR motif might be beneficial for the catalytic efficiencies of typical PTSs by the stabilization of the baccharenyl cation. Here, we develop a general strategy for improving the activity of typical PTSs. As a proof of concept, the activity of three PTSs such as lupeol synthase, β-amyrin synthase, and α-amyrin synthases was significantly increased up to 7.3-fold by site-directed saturation mutagenesis. This strategy could be applied to improve the activity of various typical PTSs. KEY POINTS: • The strategy could be applied to typical PTSs for improving the activity. • The catalytic activity of typical PTSs was significantly increased.
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Affiliation(s)
- Hao Guo
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Beijing, 100081, China
| | - Tongtong Chen
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Beijing, 100081, China
| | - Hanrong Zhu
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, Beijing, 100081, China
| | - Huiyan Wang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, 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, Beijing, 100081, China.
- Beijing Institute of Technology (Tangshan), Translational Research Center, Hebei, China.
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Spencer TA, Ditchfield R. Tryptophan Stabilization of a Biochemical Carbocation Evaluated by Analysis of π Complexes of 3-Ethylindole with the t-Butyl Cation. ACS OMEGA 2023; 8:26497-26507. [PMID: 37521644 PMCID: PMC10373456 DOI: 10.1021/acsomega.3c03259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 06/27/2023] [Indexed: 08/01/2023]
Abstract
Understanding how the highly unstable carbocation intermediates in terpenoid biosynthesis are stabilized and protected during their transient existence in enzyme active sites is an intriguing challenge which has to be addressed computationally. Our efforts have focused on evaluating the stabilization afforded via carbocation-π complexation between a biochemical carbocation and an aromatic amino acid residue. This has involved making measurements on an X-ray structure of an enzyme active site that shows a π donor proximate to a putative carbocation site and using these to build models which are analyzed computationally to provide an estimated stabilization energy (SE). Previously, we reported estimated SEs for several such carbocation-π complexes involving phenylalanine. Herein, we report the first such estimate involving tryptophan as the π donor. Because there was almost no published information about indole as a π-complexation donor, we first located computationally equilibrium π and σ complexes of 3-ethylindole with the t-butyl cation as relevant background information. Then, measurements on the X-ray structure of the enzyme CotB2 complexed with geranylgeranyl thiodiphosphate (GGSPP), specifically on the geometric relationship of the putative carbocation at C15 of GGSPP to W186, were used to build a model that afforded a computed SE of -15.3 kcal/mol.
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Song Z, Chen D, Sui S, Wang Y, Cen S, Dai J. Characterization of a Malabaricane-Type Triterpene Synthase from Astragalus membranaceus and Enzymatic Synthesis of Astramalabaricosides. JOURNAL OF NATURAL PRODUCTS 2023. [PMID: 37336771 DOI: 10.1021/acs.jnatprod.3c00331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2023]
Abstract
Triterpenoids are a large and medicinally important group of natural products with a wide range of biological and pharmacological effects. Among them, malabaricane-type triterpenoids are a rare group of terpenoids with a 6,6,5-tricyclic ring system, and a few malabaricane triterpene synthases have been characterized to date. Here, an arabidiol synthase AmAS for the formation of the malabaricane-type 6,6,5-tricyclic triterpenoid skeleton in astramalabaricosides biosynthesis was characterized from Astragalus membranaceus. Multiple sequence alignment, site-directed mutagenesis, and molecular docking of AmAS reveal that residues Q256 and Y258 are essential for AmAS activity, and the triad motif IIH725-727 was the critical residue necessary for its product specificity. Mutation of IIH725-727 with VFN led to the formation of seven tricyclic, tetracyclic, and pentacyclic triterpenoids (1-7). Glycosylation of malabaricane-type triterpenoids in the biosynthesis of astramalabaricosides was also explored. Three triterpenoids (1, 5, and 6) displayed potent inhibitory effects against influenza A virus in vitro. These findings provide insights into malabaricane-type triterpenoids biosynthesis in A. membranaceus and access to diverse bioactive triterpenoids for drug discovery.
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Affiliation(s)
- Zhijun Song
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, CAMS Key Laboratory of Enzyme and Biocatalysis of Natural Drugs, and NHC Key Laboratory of Biosynthesis of Natural Products, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Dawei Chen
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, CAMS Key Laboratory of Enzyme and Biocatalysis of Natural Drugs, and NHC Key Laboratory of Biosynthesis of Natural Products, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Songyang Sui
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, CAMS Key Laboratory of Enzyme and Biocatalysis of Natural Drugs, and NHC Key Laboratory of Biosynthesis of Natural Products, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Yujia Wang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Shan Cen
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
| | - Jungui Dai
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, CAMS Key Laboratory of Enzyme and Biocatalysis of Natural Drugs, and NHC Key Laboratory of Biosynthesis of Natural Products, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China
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Clustered regularly interspaced short palindromic repeats tools for plant metabolic engineering: achievements and perspectives. Curr Opin Biotechnol 2023; 79:102856. [PMID: 36473330 DOI: 10.1016/j.copbio.2022.102856] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 11/17/2022] [Indexed: 12/09/2022]
Abstract
The plant kingdom represents the biggest source of feedstock, food, and added-value compounds. Engineering plant metabolic pathways to increase the phytochemical production or improve the nutraceutical value of crops is challenging because of the intricate interaction networks that link multiple genes, enzymatic steps, and metabolites, even when pathways are fully elucidated. The development of clustered regularly interspaced short palindromic repeats - CRISPR-associated (CRISPR-Cas) technologies has helped to overcome limitations in metabolic engineering, providing efficient and versatile tools for multigene editing. CRISPR approaches in plants were shown to have a remarkable efficiency in genome editing of different species to improve agronomic and metabolic traits. Here, we give an overview of the different achievements and perspectives of CRISPR technology in plant metabolic engineering.
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Luo Y, Jiang Y, Chen L, Li C, Wang Y. Applications of protein engineering in the microbial synthesis of plant triterpenoids. Synth Syst Biotechnol 2022; 8:20-32. [PMID: 36381964 PMCID: PMC9634032 DOI: 10.1016/j.synbio.2022.10.001] [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: 07/03/2022] [Revised: 10/03/2022] [Accepted: 10/04/2022] [Indexed: 11/26/2022] Open
Abstract
Triterpenoids are a class of natural products widely used in fields related to medicine and health due to their biological activities such as hepatoprotection, anti-inflammation, anti-viral, and anti-tumor. With the advancement in biotechnology, microorganisms have been used as cell factories to produce diverse natural products. Despite the significant progress that has been made in the construction of microbial cell factories for the heterogeneous biosynthesis of triterpenoids, the industrial production of triterpenoids employing microorganisms has been stymied due to the shortage of efficient enzymes as well as the low expression and low catalytic activity of heterologous proteins in microbes. Protein engineering has been demonstrated as an effective way for improving the specificity, catalytic activity, and stability of the enzyme, which can be employed to overcome these challenges. This review summarizes the current progress in the studies of Oxidosqualene cyclases (OSCs), cytochrome P450s (P450s), and UDP-glycosyltransferases (UGTs), the key enzymes in the triterpenoids synthetic pathway. The main obstacles restricting the efficient catalysis of these key enzymes are analyzed, the applications of protein engineering for the three key enzymes in the microbial synthesis of triterpenoids are systematically reviewed, and the challenges and prospects of protein engineering are also discussed.
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Affiliation(s)
- Yan Luo
- Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Yaozhu Jiang
- Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Linhao Chen
- Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Chun Li
- Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China,Key Laboratory for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China
| | - Ying Wang
- Key Laboratory of Medical Molecule Science and Pharmaceutics Engineering, Institute of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China,Corresponding author.
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Guo H, Wang H, Chen T, Guo L, Blank LM, Ebert BE, Huo YX. Engineering Critical Amino Acid Residues of Lanosterol Synthase to Improve the Production of Triterpenoids in Saccharomyces cerevisiae. ACS Synth Biol 2022; 11:2685-2696. [PMID: 35921601 DOI: 10.1021/acssynbio.2c00098] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Triterpenoids are a subgroup of terpenoids and have wide applications in the food, cosmetics, and pharmaceutical industries. The heterologous production of various triterpenoids in Saccharomyces cerevisiae, as well as other microbes, has been successfully implemented as these production hosts not only produce the precursor of triterpenoids 2,3-oxidosqualene by the mevalonate pathway but also allow simple expression of plant membrane-anchored enzymes. Nevertheless, 2,3-oxidosqualene is natively converted to lanosterol catalyzed by the endogenous lanosterol synthase (Erg7p), causing low production of recombinant triterpenoids. While simple deletion of ERG7 was not effective, in this study, the critical amino acid residues of Erg7p were engineered to lower this critical enzyme activity. The engineered S. cerevisiae indeed accumulated 2,3-oxidosqualene up to 180 mg/L. Engineering triterpenoid synthesis into the ERG7-modified strain resulted in 7.3- and 3-fold increases in the titers of dammarane-type and lupane-type triterpenoids, respectively. This study presents an efficient inducer-free strategy for lowering Erg7p activity, thereby providing 2,3-oxidosqualene for the enhanced production of various triterpenoids.
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Affiliation(s)
- Hao Guo
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, 100081 Beijing, China
| | - Huiyang Wang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, 100081 Beijing, China
| | - Tongtong Chen
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, 100081 Beijing, China
| | - Liwei Guo
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, 100081 Beijing, China
| | - Lars M Blank
- Institute of Applied Microbiology-iAMB, Aachen Biology and Biotechnology - ABBt, RWTH Aachen University Worringer Weg 1, 52074 Aachen, Germany
| | - Birgitta E Ebert
- Australian Institute for Bioengineering and Nanotechnology The University of Queensland Cnr College Rd & Cooper Rd, St Luci a, QLD 4072, Australia
| | - Yi-Xin Huo
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, No. 5 South Zhongguancun Street, 100081 Beijing, China
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Chen K, Zhang M, Xu L, Yi Y, Wang L, Wang H, Wang Z, Xing J, Li P, Zhang X, Shi X, Ye M, Osbourn A, Qiao X. Identification of oxidosqualene cyclases associated with saponin biosynthesis from Astragalus membranaceus reveals a conserved motif important for catalytic function. J Adv Res 2022; 43:247-257. [PMID: 36585112 PMCID: PMC9811366 DOI: 10.1016/j.jare.2022.03.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 02/10/2022] [Accepted: 03/22/2022] [Indexed: 01/07/2023] Open
Abstract
INTRODUCTION Triterpenoids and saponins have a broad range of pharmacological activities. Unlike most legumes which contain mainly oleanane-type scaffold, Astragalus membranaceus contains not only oleanane-type but also cycloartane-type saponins, for which the biosynthetic pathways are unknown. OBJECTIVES This work aims to study the function and catalytic mechanism of oxidosqualene cyclases (OSCs), one of the most important enzymes in triterpenoid biosynthesis, in A. membranaceus. METHODS Two OSC genes, AmOSC2 and AmOSC3, were cloned from A. membranaceus. Their functions were studied by heterologous expression in tobacco and yeast, together with in vivo transient expression and virus-induced gene silencing. Site-directed mutagenesis and molecular docking were used to explain the catalytic mechanism for the conserved motif. RESULTS AmOSC2 is a β-amyrin synthase which showed higher expression levels in underground parts. It is associated with the production of β-amyrin and soyasaponins (oleanane-type) in vivo. AmOSC3 is a cycloartenol synthase expressed in both aerial and underground parts. It is related to the synthesis of astragalosides (cycloartane-type) in the roots, and to the synthesis of cycloartenol as a plant sterol precursor. From AmOSC2/3, conserved triad motifs VFM/VFN were discovered for β-amyrin/cycloartenol synthases, respectively. The motif is a critical determinant of yield as proved by 10 variants from different OSCs, where the variant containing the conserved motif increased the yield by up to 12.8-fold. Molecular docking and mutagenesis revealed that Val, Phe and Met residues acted together to stabilize the substrate, and the cation-π interactions from Phe played the major role. CONCLUSION The study provides insights into the biogenic origin of oleanane-type and cycloartane-type triterpenoids in Astragalus membranaceus. The conserved motif offers new opportunities for OSC engineering.
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Affiliation(s)
- Kuan Chen
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Meng Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Lulu Xu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Yang Yi
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Linlin Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Haotian Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Zilong Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Jiangtao Xing
- Thermo Fisher Scientific, Building A, Qiming Plaza, No.101, Wangjing Lize Middle Street, Beijing 100102, China
| | - Pi Li
- Thermo Fisher Scientific, Building A, Qiming Plaza, No.101, Wangjing Lize Middle Street, Beijing 100102, China
| | - Xiaohui Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Xiaomeng Shi
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Min Ye
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China
| | - Anne Osbourn
- Department of Biochemistry and Metabolism, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom,Corresponding authors at: State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China (X. Qiao); Department of Biochemistry and Metabolism, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom (A. Osbourn).
| | - Xue Qiao
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China,Department of Biochemistry and Metabolism, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom,Corresponding authors at: State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China (X. Qiao); Department of Biochemistry and Metabolism, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom (A. Osbourn).
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The Methionine 549 and Leucine 552 Residues of Friedelin Synthase from Maytenus ilicifolia Are Important for Substrate Binding Specificity. Molecules 2021; 26:molecules26226806. [PMID: 34833897 PMCID: PMC8617677 DOI: 10.3390/molecules26226806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 11/16/2022] Open
Abstract
Friedelin, a pentacyclic triterpene found in the leaves of the Celastraceae species, demonstrates numerous biological activities and is a precursor of quinonemethide triterpenes, which are promising antitumoral agents. Friedelin is biosynthesized from the cyclization of 2,3-oxidosqualene, involving a series of rearrangements to form a ketone by deprotonation of the hydroxylated intermediate, without the aid of an oxidoreductase enzyme. Mutagenesis studies among oxidosqualene cyclases (OSCs) have demonstrated the influence of amino acid residues on rearrangements during substrate cyclization: loss of catalytic activity, stabilization, rearrangement control or specificity changing. In the present study, friedelin synthase from Maytenus ilicifolia (Celastraceae) was expressed heterologously in Saccharomyces cerevisiae. Site-directed mutagenesis studies were performed by replacing phenylalanine with tryptophan at position 473 (Phe473Trp), methionine with serine at position 549 (Met549Ser) and leucine with phenylalanine at position 552 (Leu552Phe). Mutation Phe473Trp led to a total loss of function; mutants Met549Ser and Leu552Phe interfered with the enzyme specificity leading to enhanced friedelin production, in addition to α-amyrin and β-amyrin. Hence, these data showed that methionine 549 and leucine 552 are important residues for the function of this synthase.
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Wang J, Guo Y, Yin X, Wang X, Qi X, Xue Z. Diverse triterpene skeletons are derived from the expansion and divergent evolution of 2,3-oxidosqualene cyclases in plants. Crit Rev Biochem Mol Biol 2021; 57:113-132. [PMID: 34601979 DOI: 10.1080/10409238.2021.1979458] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Triterpenoids are one of the largest groups of secondary metabolites and exhibit diverse structures, which are derived from C30 skeletons that are biosynthesized via the isoprenoid pathway by cyclization of 2,3-oxidosqualene. Triterpenoids have a wide range of biological activities, and are used in functional foods, drugs, and as industrial materials. Due to the low content levels in their native plants and limited feasibility and efficiency of chemical synthesis, heterologous biosynthesis of triterpenoids is the most promising strategy. Herein, we classified 121 triterpene alcohols/ketones according to their conformation and ring numbers, among which 51 skeletons have been experimentally characterized as the products of oxidosqualene cyclases (OSCs). Interestingly, 24 skeletons that have not been reported from nature source were generated by OSCs in heterologous expression. Comprehensive evolutionary analysis of the identified 152 OSCs from 75 species in 25 plant orders show that several pentacyclic triterpene synthases repeatedly originated in multiple plant lineages. Comparative analysis of OSC catalytic reaction revealed that stabilization of intermediate cations, steric hindrance, and conformation of active center amino acid residues are primary factors affecting triterpene formation. Optimization of OSC could be achieved by changing of side-chain orientations of key residues. Recently, methods, such as rationally design of pathways, regulation of metabolic flow, compartmentalization engineering, etc., were introduced in improving chassis for the biosynthesis of triterpenoids. We expect that extensive study of natural variation of large number of OSCs and catalytical mechanism will provide basis for production of high level of triterpenoids by application of synthetic biology strategies.
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Affiliation(s)
- Jing Wang
- Ministry of Education, Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Northeast Forestry University, Harbin, PR China.,Heilongjiang Key Laboratory of Plant Bioactive Substance Biosynthesis and Utilization, Northeast Forestry University, Harbin, PR China.,Institute of Forestry and Pomology, Beijing Academy of Agriculture and Forestry Sciences, Beijing, PR China
| | - Yanhong Guo
- Ministry of Education, Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Northeast Forestry University, Harbin, PR China.,Heilongjiang Key Laboratory of Plant Bioactive Substance Biosynthesis and Utilization, Northeast Forestry University, Harbin, PR China
| | - Xue Yin
- Ministry of Education, Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Northeast Forestry University, Harbin, PR China.,Heilongjiang Key Laboratory of Plant Bioactive Substance Biosynthesis and Utilization, Northeast Forestry University, Harbin, PR China
| | - Xiaoning Wang
- Department of Natural Product Chemistry, Key Laboratory of Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, Jinan, PR China
| | - Xiaoquan Qi
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, PR China
| | - Zheyong Xue
- Ministry of Education, Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Northeast Forestry University, Harbin, PR China.,Heilongjiang Key Laboratory of Plant Bioactive Substance Biosynthesis and Utilization, Northeast Forestry University, Harbin, PR China
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11
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Chen K, Zhang M, Ye M, Qiao X. Site-directed mutagenesis and substrate compatibility to reveal the structure-function relationships of plant oxidosqualene cyclases. Nat Prod Rep 2021; 38:2261-2275. [PMID: 33988197 DOI: 10.1039/d1np00015b] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: up to May 2020Oxidosqualene cyclases (OSCs) catalyze one of the most complex polycyclization reactions in nature, using the linear 2,3-oxidosqualene to generate an array of triterpene skeletons in plants. Despite the structural diversity of the products, the protein sequences of plant OSCs are highly conserved, where a few key amino acids could govern the product selectivity. Due to the absence of crystal structures, site-directed mutagenesis and substrate structural modification become key approaches to understand the cyclization mechanism. In this review, 98 mutation sites in 25 plant OSCs have been summarized, and the conserved key residues have been identified by sequence alignment. Structure-function relationships are further discussed. Meanwhile, the substrate selectivity has been summarized to probe the active site cavity of plant OSCs. A total of 77 references are included.
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Affiliation(s)
- Kuan Chen
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China.
| | - Meng Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China.
| | - Min Ye
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China.
| | - Xue Qiao
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing 100191, China.
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12
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Spencer TA, Ditchfield R. A simpler method affords evaluation of π stabilization by phenylalanine of several biochemical carbocations. Org Biomol Chem 2020; 18:7597-7607. [PMID: 32955057 DOI: 10.1039/d0ob01565b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
Carbocations are important intermediates in the biosynthesis of terpenes and steroids, and it is challenging to try to understand how these relatively unstable species survive even transiently during biochemical reactions. Carbocation-π interaction with aromatic amino acid residues is an important factor in helping to stabilize these positively charged species. However, the short lifetimes of these active site carbocations makes experimental evaluation of the stabilization afforded by such interaction impossible. Computational studies, however, have provided some insight into this phenomenon. Herein we report a simple, computationally efficient method to estimate such stabilization energies afforded by phenylalanine to biochemical carbocation intermediates. A model is constructed in which the biochemical carbocation is replaced by an appropriate carbocation mimic (t-butyl or dimethylallyl). This substitute carbocation is then aligned with an ethylbenzene serving as a surrogate for each proximate phenylalanine in a geometry that replicates as closely as possible the orientation of that phenylalanine using measurements made on an X-ray structure of an enzyme active site in which a carbocation surrogate is bound. Density functional theory computations on such models were then used to yield estimates of stabilization energies. Application of this method to the tertiary carbocation formed in the reaction catalyzed by geranyl diphosphate C-methyl transferase gave a stabilization energy (-12.3 kcal mol-1) that was essentially identical to that obtained previously by analysis of a much more computationally demanding model of the active site. As a check on the accuracy of the simpler method, it was applied with similar success to the farnesyl cation formed in the reaction catalyzed by aristolochene synthase that is stabilized by cation-π interaction with two phenylalanines. Application of this method is also described to estimate carbocation-π stabilization, by the same two phenylalanines, of the final carbocation intermediate leading to aristolochene through analysis of the X-ray structure of an inhibitor of that carbocation bound in the active site of aristolochene synthase. Finally, the stabilization, by either of two phenylalanines, of six carbocation intermediates in the oxidosqualene cyclase-catalyzed formation of lanosterol is estimated by comparable analysis of an X-ray structure of that reaction product bound in the enzyme active site.
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Affiliation(s)
- Thomas A Spencer
- Department of Chemistry, 6128 Burke Laboratory, Dartmouth College, Hanover, NH 03755, USA.
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13
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Srisawat P, Fukushima EO, Yasumoto S, Robertlee J, Suzuki H, Seki H, Muranaka T. Identification of oxidosqualene cyclases from the medicinal legume tree Bauhinia forficata: a step toward discovering preponderant α-amyrin-producing activity. THE NEW PHYTOLOGIST 2019; 224:352-366. [PMID: 31230357 DOI: 10.1111/nph.16013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 06/15/2019] [Indexed: 05/27/2023]
Abstract
Triterpenoids are widely distributed among plants of the legume family. However, most studies have focused on triterpenoids and their biosynthetic enzymes in model legumes. We evaluated the triterpenoid aglycones profile of the medicinal legume tree Bauhinia forficata by gas chromatography-mass spectrometry. Through transcriptome analyses, homology-based cloning, and heterologous expression, we discovered four oxidosqualene cyclases (OSCs) which are responsible for the diversity of triterpenols in B. forficata. We also investigated the effects of the unique motif TLCYCR on α-amyrin synthase activity. B. forficata highly accumulated α-amyrin. We discovered an OSC with a preponderant α-amyrin-producing activity, which accounted for at least 95% of the total triterpenols. We also discovered three other functional OSCs (BfOSC1, BfOSC2, and BfOSC4) that produce β-amyrin, germanicol, and cycloartenol. Furthermore, by replacing the unique motif TLCYCR from BfOSC3 with the MWCYCR motif, we altered the function of BfOSC3 such that it no longer produced α-amyrin. Our results provide new insights into OSC cyclization, which is responsible for the diversity of triterpenoid metabolites in B. forficata, a non-model legume plant.
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Affiliation(s)
- Pisanee Srisawat
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, 565-0871, Japan
| | - Ery Odette Fukushima
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, 565-0871, Japan
- Universidad Regional Amazónica IKIAM, Tena, 150150, Ecuador
| | - Shuhei Yasumoto
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, 565-0871, Japan
| | - Jekson Robertlee
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, 565-0871, Japan
- Department of Frontier Research, Kazusa DNA Research Institute, Kisarazu, 292-0818, Japan
| | - Hideyuki Suzuki
- Department of Research & Development, Kazusa DNA Research Institute, Kisarazu, 292-0818, Japan
| | - Hikaru Seki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, 565-0871, Japan
| | - Toshiya Muranaka
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, 565-0871, Japan
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14
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Kazim M, Siegler MA, Lectka T. A Protonated Quinone Methide Stabilized by a Combination of Partial Aromatization and π-Interaction: Spectroscopic and Crystallographic Analysis. J Org Chem 2019; 84:8284-8288. [PMID: 31117575 DOI: 10.1021/acs.joc.9b00923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have expanded the repertoire of cation-π interactions to include a carbocation-π system resulting from the protonation of a π-stacked para-quinone methide (p-QM). This unusual carbocation is stabilized by a combination of partial aromatization of the QM moiety and through-space interaction with the π-system of the adjacent aromatic ring. Single crystal X-ray analysis of the protonated form reveals a structure consisting of a hydrogen-bound complex involving two molecules of the precursor and one proton.
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Affiliation(s)
- Muhammad Kazim
- Department of Chemistry , Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| | - Maxime A Siegler
- Department of Chemistry , Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
| | - Thomas Lectka
- Department of Chemistry , Johns Hopkins University , 3400 North Charles Street , Baltimore , Maryland 21218 , United States
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15
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Affiliation(s)
- Shinji Yamada
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
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16
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Identification of Key Amino Acid Residues Determining Product Specificity of 2,3-Oxidosqualene Cyclase in Siraitia grosvenorii. Catalysts 2018. [DOI: 10.3390/catal8120577] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Sterols and triterpenes are structurally diverse bioactive molecules generated through cyclization of linear 2,3-oxidosqualene. Based on carbocationic intermediates generated during the initial substrate preorganization step, oxidosqualene cyclases (OSCs) are roughly segregated into a dammarenyl cation group that predominantly catalyzes triterpenoid precursor products and a protosteryl cation group which mostly generates sterol precursor products. The mechanism of conversion between two scaffolds is not well understood. Previously, we have characterized a promiscuous OSC from Siraitia grosvenorii (SgCS) that synthesizes a novel cucurbitane-type triterpene cucurbitadienol as its main product. By integration of homology modeling, molecular docking and site-directed mutagenesis, we discover that five key amino acid residues (Asp486, Cys487, Cys565, Tyr535, and His260) may be responsible for interconversions between chair–boat–chair and chair–chair–chair conformations. The discovery of euphol, dihydrolanosterol, dihydroxyeuphol and tirucallenol unlocks a new path to triterpene diversity in nature. Our findings also reveal mechanistic insights into the cyclization of oxidosqualene into cucurbitane-type and lanostane-type skeletons, and provide a new strategy to identify key residues determining OSC specificity.
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17
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Xue Z, Tan Z, Huang A, Zhou Y, Sun J, Wang X, Thimmappa RB, Stephenson MJ, Osbourn A, Qi X. Identification of key amino acid residues determining product specificity of 2,3-oxidosqualene cyclase in Oryza species. THE NEW PHYTOLOGIST 2018; 218:1076-1088. [PMID: 29528490 DOI: 10.1111/nph.15080] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 02/05/2018] [Indexed: 05/27/2023]
Abstract
Triterpene synthases, also known as 2,3-oxidosqualene cyclases (OSCs), synthesize diverse triterpene skeletons that form the basis of an array of functionally divergent steroids and triterpenoids. Tetracyclic and pentacyclic triterpene skeletons are synthesized via protosteryl and dammarenyl cations, respectively. The mechanism of conversion between two scaffolds is not well understood. Here, we report a promiscuous OSC from rice (Oryza sativa) (OsOS) that synthesizes a novel pentacyclic triterpene orysatinol as its main product. The OsOS gene is widely distributed in indica subspecies of cultivated rice and in wild rice accessions. Previously, we have characterized a different OSC, OsPS, a tetracyclic parkeol synthase found in japonica subspecies. Phylogenetic and protein structural analyses identified three key amino acid residues (#732, #365, #124) amongst 46 polymorphic sites that determine functional conversion between OsPS and OsOS, specifically, the chair-semi(chair)-chair and chair-boat-chair interconversions. The different orientation of a fourth amino acid residue Y257 was shown to be important for functional conversion The discovery of orysatinol unlocks a new path to triterpene diversity in nature. Our findings also reveal mechanistic insights into the cyclization of oxidosqualene into tetra- and pentacyclic skeletons, and provide a new strategy to identify key residues determining OSC specificity.
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Affiliation(s)
- Zheyong Xue
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- Department of Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Zhengwei Tan
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Henan Sesame Research Center, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, China
| | - Ancheng Huang
- Department of Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Yuan Zhou
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Juncong Sun
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaoning Wang
- Department of Natural Product Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, 44 West Wenhua Road, Jinan, 250012, China
| | - Ramesha B Thimmappa
- Department of Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Michael J Stephenson
- Department of Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Anne Osbourn
- Department of Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Xiaoquan Qi
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
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18
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Aiba Y, Watanabe T, Terasawa Y, Nakano C, Hoshino T. Strictly Conserved Residues in Euphorbia tirucalli
β-Amyrin Cyclase: Trp612 Stabilizes Transient Cation through Cation-π Interaction and CH-π Interaction of Tyr736 with Leu734 Confers Robust Local Protein Architecture. Chembiochem 2018; 19:486-495. [DOI: 10.1002/cbic.201700572] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Yukari Aiba
- Graduate School of Science and Technology and Department of Applied Biological Chemistry; Faculty of Agriculture; Niigata University; Ikarashi 2-8050 Nishi-ku Niigata 950-2181 Japan
| | - Takumi Watanabe
- Graduate School of Science and Technology and Department of Applied Biological Chemistry; Faculty of Agriculture; Niigata University; Ikarashi 2-8050 Nishi-ku Niigata 950-2181 Japan
| | - Yuri Terasawa
- Graduate School of Science and Technology and Department of Applied Biological Chemistry; Faculty of Agriculture; Niigata University; Ikarashi 2-8050 Nishi-ku Niigata 950-2181 Japan
| | - Chiaki Nakano
- Graduate School of Science and Technology and Department of Applied Biological Chemistry; Faculty of Agriculture; Niigata University; Ikarashi 2-8050 Nishi-ku Niigata 950-2181 Japan
| | - Tsutomu Hoshino
- Graduate School of Science and Technology and Department of Applied Biological Chemistry; Faculty of Agriculture; Niigata University; Ikarashi 2-8050 Nishi-ku Niigata 950-2181 Japan
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19
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Hoshino T, Nakagawa K, Aiba Y, Itoh D, Nakada C, Masukawa Y. Euphorbia tirucalli
β-Amyrin Synthase: Critical Roles of Steric Sizes at Val483 and Met729 and the CH-π Interaction between Val483 and Trp534 for Catalytic Action. Chembiochem 2017; 18:2145-2155. [DOI: 10.1002/cbic.201700368] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Indexed: 02/02/2023]
Affiliation(s)
- Tsutomu Hoshino
- Graduate School of Science and Technology and; Department of Applied Biological Chemistry; Faculty of Agriculture; Niigata University; Ikarashi 2-8050 Nishi-ku Niigata 950-2181 Japan), E-mail: address
| | - Kazuya Nakagawa
- Graduate School of Science and Technology and; Department of Applied Biological Chemistry; Faculty of Agriculture; Niigata University; Ikarashi 2-8050 Nishi-ku Niigata 950-2181 Japan), E-mail: address
| | - Yukari Aiba
- Graduate School of Science and Technology and; Department of Applied Biological Chemistry; Faculty of Agriculture; Niigata University; Ikarashi 2-8050 Nishi-ku Niigata 950-2181 Japan), E-mail: address
| | - Daichi Itoh
- Graduate School of Science and Technology and; Department of Applied Biological Chemistry; Faculty of Agriculture; Niigata University; Ikarashi 2-8050 Nishi-ku Niigata 950-2181 Japan), E-mail: address
| | - Chika Nakada
- Graduate School of Science and Technology and; Department of Applied Biological Chemistry; Faculty of Agriculture; Niigata University; Ikarashi 2-8050 Nishi-ku Niigata 950-2181 Japan), E-mail: address
| | - Yukari Masukawa
- Graduate School of Science and Technology and; Department of Applied Biological Chemistry; Faculty of Agriculture; Niigata University; Ikarashi 2-8050 Nishi-ku Niigata 950-2181 Japan), E-mail: address
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20
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Hoshino T. β-Amyrin biosynthesis: catalytic mechanism and substrate recognition. Org Biomol Chem 2017; 15:2869-2891. [DOI: 10.1039/c7ob00238f] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In the past five years, there have been remarkable advances in the study of β-amyrin synthase. This review outlines the catalytic mechanism and substrate recognition in β-amyrin biosynthesis, which have been attained by the site-directed mutagenesis and substrate analog experiments.
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Affiliation(s)
- Tsutomu Hoshino
- Graduate School of Science and Technology and Department of Applied Biological Chemistry
- Faculty of Agriculture
- Niigata University
- Niigata 950-2181
- Japan
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21
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Ito R, Nakada C, Hoshino T. β-Amyrin synthase from Euphorbia tirucalli L. functional analyses of the highly conserved aromatic residues Phe413, Tyr259 and Trp257 disclose the importance of the appropriate steric bulk, and cation-π and CH-π interactions for the efficient catalytic action of the polyolefin cyclization cascade. Org Biomol Chem 2016; 15:177-188. [PMID: 27942657 DOI: 10.1039/c6ob02539k] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Many of the functions of the active site residues in β-amyrin synthase and its catalytic mechanism remain unclear. Herein, we examined the functions of the highly conserved Phe413, Tyr259, and Trp257 residues in the β-amyrin synthase of Euphorbia tirucalli. The site-specific mutants F413V and F413M [corrected] showed nearly the same enzymatic activities as the wild type, indicating that π-electrons are not needed for the catalytic reaction. However, the F413A [corrected] mutant yielded a large amount of the tetracyclic dammarane skeleton, with decreased production of β-amyrin. This indicates that the Phe413 [corrected] residue is located near the D-ring formation site and works to position the oxidosqualene substrate correctly within the reaction cavity. On the other hand, the major catalysis-related function of the Tyr259 and Trp257 residues is to yield their π-electrons to the cationic intermediates. The Y259F variant showed nearly equivalent activity to that of the wild type, but aliphatic mutants such as the Ala, Val, and Leu variants showed significantly decreased the activity and yielded the tetracyclic dammarane scaffold, strongly demonstrating that the Tyr259 residue stabilizes the baccharenyl secondary cation via cation-π interaction. The aliphatic variants of Trp257 exhibited remarkably decreased enzymatic activity, and lupeol was produced in a high production ratio, indicating that Trp257 stabilizes the oleanyl cation via cation-π interaction. The aromatic Phe and Tyr mutants exhibited high activities owing to their more increased π-electron density relative to that of the aliphatic mutants, but lupeol was produced in a significantly high yield besides β-amyrin. The Trp residue is likely to be responsible for the robust binding of Me-30 through CH-π interaction. The decreased π-electron density of the Phe and Tyr mutants compared to that of Trp would have resulted in the high production of lupeol.
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Affiliation(s)
- Ryousuke Ito
- Graduate School of Science and Technology and Department of Applied Biological Chemistry, Faculty of Agriculture, Niigata University, Ikarashi 2-8050, Nishi-ku, Niigata 950-2181, Japan.
| | - Chika Nakada
- Graduate School of Science and Technology and Department of Applied Biological Chemistry, Faculty of Agriculture, Niigata University, Ikarashi 2-8050, Nishi-ku, Niigata 950-2181, Japan.
| | - Tsutomu Hoshino
- Graduate School of Science and Technology and Department of Applied Biological Chemistry, Faculty of Agriculture, Niigata University, Ikarashi 2-8050, Nishi-ku, Niigata 950-2181, Japan.
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22
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An Intronless β-amyrin Synthase Gene is More Efficient in Oleanolic Acid Accumulation than its Paralog in Gentiana straminea. Sci Rep 2016; 6:33364. [PMID: 27624821 PMCID: PMC5022052 DOI: 10.1038/srep33364] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 08/24/2016] [Indexed: 11/25/2022] Open
Abstract
Paralogous members of the oxidosqualene cyclase (OSC) family encode a diversity of enzymes that are important in triterpenoid biosynthesis. This report describes the isolation of the Gentiana straminea gene GsAS2 that encodes a β-amyrin synthase (βAS) enzyme. Unlike its previously isolated paralog GsAS1, GsAS2 lacks introns. Its predicted protein product was is a 759 residue polypeptide that shares high homology with other known β-amyrin synthases (βASs). Heterologously expressed GsAS2 generates more β-amyrin in yeast than does GsAS1. Constitutive over-expression of GsAS2 resulted in a 5.7 fold increase in oleanolic acid accumulation, while over-expression of GsAS1 led to a 3 fold increase. Additionally, RNAi-directed suppression of GsAS2 and GsAS1 in G. straminea decreased oleonolic acid levels by 65.9% and 21% respectively, indicating that GsAS2 plays a more important role than GsAS1 in oleanolic acid biosynthesis in G. straminea. We uses a docking model to explore the catalytic mechanism of GsAS1/2 and predicted that GsAS2, with its Y560, have higher efficiency than GsAS1 and mutated versions of GsAS2 in β-amyrin produce. When the key residue in GsAS2 was mutagenized, it produced about 41.29% and 71.15% less β-amyrin than native, while the key residue in GsAS1 was mutagenized to that in GsAS2, the mutant produced 38.02% more β-amyrin than native GsAS1.
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23
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Kaneko I, Hoshino T. β-Amyrin Biosynthesis: Promiscuity for Steric Bulk at Position 23 in the Oxidosqualene Substrate and the Significance of Hydrophobic Interaction between the Methyl Group at Position 30 and the Binding Site. J Org Chem 2016; 81:6657-71. [DOI: 10.1021/acs.joc.6b01313] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ikki Kaneko
- Department
of Applied Biological
Chemistry, Faculty of Agriculture and Graduate School of Science and
Technology, Niigata University, Ikarashi 2-8050, Nishi-ku, Niigata, Japan 950-2181
| | - Tsutomu Hoshino
- Department
of Applied Biological
Chemistry, Faculty of Agriculture and Graduate School of Science and
Technology, Niigata University, Ikarashi 2-8050, Nishi-ku, Niigata, Japan 950-2181
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24
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Ditchfield R, Spencer TA. Carbocation–π interaction: evaluation of the stabilization by phenylalanine of a biochemical carbocation intermediate. Org Biomol Chem 2016; 14:9543-9548. [DOI: 10.1039/c6ob01761d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Computational analyses, using primarily density functional theory, have been used to determine the stabilization associated with the carbocation–π interaction of a biochemical carbocation intermediate binding to a phenylalanine residue in an enzyme active site.
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Affiliation(s)
- Robert Ditchfield
- Department of Chemistry
- 6128 Burke Laboratory
- Dartmouth College
- Hanover
- USA
| | - Thomas A. Spencer
- Department of Chemistry
- 6128 Burke Laboratory
- Dartmouth College
- Hanover
- USA
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25
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Hong YJ, Tantillo DJ. Tension between Internal and External Modes of Stabilization in Carbocations Relevant to Terpene Biosynthesis: Modulating Minima Depth via C–H···π Interactions. Org Lett 2015; 17:5388-91. [DOI: 10.1021/acs.orglett.5b02740] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Young J. Hong
- Department
of Chemistry, Univeristy of California—Davis, Davis, California 95616, United States
| | - Dean J. Tantillo
- Department
of Chemistry, Univeristy of California—Davis, Davis, California 95616, United States
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26
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Hoshino T, Miyahara Y, Hanaoka M, Takahashi K, Kaneko I. β-Amyrin Biosynthesis: The Methyl-30 Group of (3S)-2,3-Oxidosqualene Is More Critical to Its Correct Folding To Generate the Pentacyclic Scaffold than the Methyl-24 Group. Chemistry 2015; 21:15769-84. [DOI: 10.1002/chem.201502389] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Indexed: 11/11/2022]
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27
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Shan H, Wilson WK, Castillo DA, Matsuda SPT. Are Isoursenol and γ-Amyrin Rare Triterpenes in Nature or Simply Overlooked by Usual Analytical Methods? Org Lett 2015; 17:3986-9. [PMID: 26235440 DOI: 10.1021/acs.orglett.5b01851] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Among pentacyclic triterpenes commonly found in plants, γ-amyrin and isoursenol are seldom reported and considered rare in nature. It was hypothesized that these triterpenes are instead routinely overlooked due to inadequate spectral characterization. γ-Amyrin was prepared by HCOOH isomerization of α-amyrin, and isoursenol was isolated from products of a heterologously expressed oxidosqualene cyclase. With precise NMR and GC-MS data, a metabolomics strategy was used to identify isoursenol and γ-amyrin in a wide range of plants.
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Affiliation(s)
- Hui Shan
- †Biosciences Department and ‡Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - William K Wilson
- †Biosciences Department and ‡Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Dorianne A Castillo
- †Biosciences Department and ‡Department of Chemistry, Rice University, Houston, Texas 77005, United States
| | - Seiichi P T Matsuda
- †Biosciences Department and ‡Department of Chemistry, Rice University, Houston, Texas 77005, United States
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28
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Hoshino T, Yamaguchi Y, Takahashi K, Ito R. β-Amyrin Biosynthesis: The Critical Role of Steric Volume at C-19 of 2,3-Oxidosqualene for Its Correct Folding To Generate the Pentacyclic Scaffold. Org Lett 2014; 16:3548-51. [DOI: 10.1021/ol501498q] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tsutomu Hoshino
- Graduate School of Science
and Technology, and Department of Applied Biological Chemistry, Faculty
of Agriculture, Niigata University, Ikarashi 2-8050, Nishi-ku, Niigata 950-2181, Japan
| | - Yuki Yamaguchi
- Graduate School of Science
and Technology, and Department of Applied Biological Chemistry, Faculty
of Agriculture, Niigata University, Ikarashi 2-8050, Nishi-ku, Niigata 950-2181, Japan
| | - Kazunari Takahashi
- Graduate School of Science
and Technology, and Department of Applied Biological Chemistry, Faculty
of Agriculture, Niigata University, Ikarashi 2-8050, Nishi-ku, Niigata 950-2181, Japan
| | - Ryousuke Ito
- Graduate School of Science
and Technology, and Department of Applied Biological Chemistry, Faculty
of Agriculture, Niigata University, Ikarashi 2-8050, Nishi-ku, Niigata 950-2181, Japan
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29
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Ito R, Masukawa Y, Nakada C, Amari K, Nakano C, Hoshino T. β-Amyrin synthase from Euphorbia tirucalli. Steric bulk, not the π-electrons of Phe, at position 474 has a key role in affording the correct folding of the substrate to complete the normal polycyclization cascade. Org Biomol Chem 2014; 12:3836-46. [DOI: 10.1039/c4ob00064a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The importance of the steric bulk at 474 residue is described for completion of the cyclization cascade, but not the π-electrons of the Phe residue.
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Affiliation(s)
- Ryousuke Ito
- Graduate School of Science and Technology
- and Department of Applied Biological Chemistry
- Faculty of Agriculture
- Niigata University
- Niigata 950-2181, Japan
| | - Yukari Masukawa
- Graduate School of Science and Technology
- and Department of Applied Biological Chemistry
- Faculty of Agriculture
- Niigata University
- Niigata 950-2181, Japan
| | - Chika Nakada
- Graduate School of Science and Technology
- and Department of Applied Biological Chemistry
- Faculty of Agriculture
- Niigata University
- Niigata 950-2181, Japan
| | - Kanako Amari
- Graduate School of Science and Technology
- and Department of Applied Biological Chemistry
- Faculty of Agriculture
- Niigata University
- Niigata 950-2181, Japan
| | - Chiaki Nakano
- Graduate School of Science and Technology
- and Department of Applied Biological Chemistry
- Faculty of Agriculture
- Niigata University
- Niigata 950-2181, Japan
| | - Tsutomu Hoshino
- Graduate School of Science and Technology
- and Department of Applied Biological Chemistry
- Faculty of Agriculture
- Niigata University
- Niigata 950-2181, Japan
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