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Robin AY, Giustini C, Graindorge M, Matringe M, Dumas R. Crystal structure of norcoclaurine-6-O-methyltransferase, a key rate-limiting step in the synthesis of benzylisoquinoline alkaloids. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 87:641-53. [PMID: 27232113 DOI: 10.1111/tpj.13225] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 05/23/2016] [Accepted: 05/25/2016] [Indexed: 05/25/2023]
Abstract
Growing pharmaceutical interest in benzylisoquinoline alkaloids (BIA) coupled with their chemical complexity make metabolic engineering of microbes to create alternative platforms of production an increasingly attractive proposition. However, precise knowledge of rate-limiting enzymes and negative feedback inhibition by end-products of BIA metabolism is of paramount importance for this emerging field of synthetic biology. In this work we report the structural characterization of (S)-norcoclaurine-6-O-methyltransferase (6OMT), a key rate-limiting step enzyme involved in the synthesis of reticuline, the final intermediate to be shared between the different end-products of BIA metabolism, such as morphine, papaverine, berberine and sanguinarine. Four different crystal structures of the enzyme from Thalictrum flavum (Tf 6OMT) were solved: the apoenzyme, the complex with S-adenosyl-l-homocysteine (SAH), the complexe with SAH and the substrate and the complex with SAH and a feedback inhibitor, sanguinarine. The Tf 6OMT structural study provides a molecular understanding of its substrate specificity, active site structure and reaction mechanism. This study also clarifies the inhibition of Tf 6OMT by previously suggested feedback inhibitors. It reveals its high and time-dependent sensitivity toward sanguinarine.
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Affiliation(s)
- Adeline Y Robin
- Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, CNRS UMR5168, CEA/DRF/BIG, INRA UMR 1417, 17, Avenue des Martyrs, 38054 Grenoble, France
| | - Cécile Giustini
- Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, CNRS UMR5168, CEA/DRF/BIG, INRA UMR 1417, 17, Avenue des Martyrs, 38054 Grenoble, France
| | - Matthieu Graindorge
- Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, CNRS UMR5168, CEA/DRF/BIG, INRA UMR 1417, 17, Avenue des Martyrs, 38054 Grenoble, France
| | - Michel Matringe
- Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, CNRS UMR5168, CEA/DRF/BIG, INRA UMR 1417, 17, Avenue des Martyrs, 38054 Grenoble, France.
| | - Renaud Dumas
- Laboratoire de Physiologie Cellulaire et Végétale, Université Grenoble Alpes, CNRS UMR5168, CEA/DRF/BIG, INRA UMR 1417, 17, Avenue des Martyrs, 38054 Grenoble, France.
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Wang L, Zhang T, Li J, He C, He H, Zhang J. Catalytic mechanism of human N-acetylserotonin methyltransferase: a theoretical investigation. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1036143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Zhang Y, Han MZ, Zhu SL, Li M, Dong X, Luo XC, Kong Z, Lu YX, Wang SY, Tong WY. Studies on the function and catalytic mechanism of O-methyltransferases SviOMT02, SviOMT03 and SviOMT06 from Streptomyces virginiae IBL14. Enzyme Microb Technol 2015; 73-74:72-9. [PMID: 26002507 DOI: 10.1016/j.enzmictec.2015.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 03/08/2015] [Accepted: 03/31/2015] [Indexed: 10/23/2022]
Abstract
To identify the fuctions of the nine putative O-methyltransferase genes in Streptomyces virginiae IBL14, the evolutionary and functional relationship of these genes in its 8.0 Mb linear chromosome was set up via sequence comparison with those of other Streptomyces species. Further, the functions and catalytic mechanism of the three genes sviOMT02, sviOMT03 and sviOMT06 from this strain were studied through experimental and computational approaches. As a result, the nine putative O-methyltransferases belong to methyltransf_2 superfamily, amdomet-MTases superfamily, and leucine carboxyl methyltransferase superfamily, and are phylogenetically close to those of Streptomyces sp. C. The products of genes sviOMT03 and sviOMT06 could catalyze O-methylation of caffeic acid to form ferulic acid. Computational analysis indicated that the O-methylation mechanism of SviOMT03 and SviOMT06 proceeds from a direct transfer of the SAM-methyl group to caffeic acid with inversion of symmetry aided by a divalent metal ion in a SN2-like mechanism. Particularly, the conservative polar amino acid residues in SviOMT03 and SviOMT06, including Lys143 that reacts with caffeic acid, Ser74, Asp140 and Tyr149 that react with S-adenosyl methionine, and His142 (SviOMT03) or His171 (SviOMT06) that transfers the 3-hydroxyl proton of substrate caffeic acid, probably be essential in their O-methylation.
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Affiliation(s)
- Yan Zhang
- Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Mao-Zhen Han
- Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Shu-Liang Zhu
- Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Man Li
- Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Xiang Dong
- Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Xue-Cai Luo
- Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Zhe Kong
- Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Yun-Xia Lu
- Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Shu-Yan Wang
- Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei 230601, China
| | - Wang-Yu Tong
- Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, 111 Jiulong Road, Hefei 230601, China.
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Brandt W, Manke K, Vogt T. A catalytic triad--Lys-Asn-Asp--Is essential for the catalysis of the methyl transfer in plant cation-dependent O-methyltransferases. PHYTOCHEMISTRY 2015; 113:130-139. [PMID: 25596806 DOI: 10.1016/j.phytochem.2014.12.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 12/10/2014] [Accepted: 12/16/2014] [Indexed: 06/04/2023]
Abstract
Crystal structure data of cation-dependent catechol O-methyltransferases (COMTs) from mammals and related caffeoyl coenzyme A OMTs (CCoAOMTs) from plants have suggested operative molecular mechanisms. These include bivalent cations that facilitate deprotonation of vicinal aromatic dihydroxy systems and illustrate a conserved arrangement of hydroxyl and carboxyl ligands consistent with the requirements of a metal-activated catalytic mechanism. The general concept of metal-dependent deprotonation via a complexed aspartate is only one part of a more pronounced proton relay, as shown by semiempirical and DFT quantum mechanical calculations and experimental validations. A previously undetected catalytic triad, consisting of Lys157-Asn181-Asp228 residues is required for complete methyl transfer in case of a cation-dependent phenylpropanoid and flavonoid OMT, as described in this report. This triad appears essential for efficient methyl transfer to catechol-like hydroxyl group in phenolics. The observation is consistent with a catalytic lysine in the case of mammalian COMTs, but jettisons existing assumptions on the initial abstraction of the meta-hydroxyl proton to the metal stabilizing Asp154 (PFOMT) or comparable Asp-carboxyl groups in type of cation-dependent enzymes in plants. The triad is conserved among all characterized plant CCoAOMT-like enzymes, which are required not only for methylation of soluble phenylpropanoids like coumarins or monolignol monomers, but is also present in the similar microbial and mammalian cation-dependent enzymes which methylate a comparable set of substrates.
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Affiliation(s)
- Wolfgang Brandt
- Leibniz Institute of Plant Biochemistry, Dept. Bioorganic Chemistry, Weinberg 3, D-06120 Halle(Saale), Germany.
| | - Kerstin Manke
- Leibniz Institute of Plant Biochemistry, Dept. Cell and Metabolic Biology, Weinberg 3, D-06120 Halle(Saale), Germany
| | - Thomas Vogt
- Leibniz Institute of Plant Biochemistry, Dept. Cell and Metabolic Biology, Weinberg 3, D-06120 Halle(Saale), Germany
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Zhang W, Cao S, Qiu L, Qi F, Li Z, Yang Y, Huang S, Bai F, Liu C, Wan X, Li S. Functional Characterization of MpaG′, the O-Methyltransferase Involved in the Biosynthesis of Mycophenolic Acid. Chembiochem 2015; 16:565-9. [DOI: 10.1002/cbic.201402600] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Indexed: 11/07/2022]
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