- Multienzyme One-Pot Cascades Incorporating Methyltransferases for the Strategic Diversification of Tetrahydroisoquinoline Alkaloids
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The tetrahydroisoquinoline (THIQ) ring system is present in a large variety of structurally diverse natural products exhibiting a wide range of biological activities. Routes to mimic the biosynthetic pathways to such alkaloids, by building cascade reactions in vitro, represents a successful strategy and can offer better stereoselectivities than traditional synthetic methods. S-Adenosylmethionine (SAM)-dependent methyltransferases are crucial in the biosynthesis and diversification of THIQs; however, their application is often limited in vitro by the high cost of SAM and low substrate scope. In this study, we describe the use of methyltransferases in vitro in multi-enzyme cascades, including for the generation of SAM in situ. Up to seven enzymes were used for the regioselective diversification of natural and non-natural THIQs on an enzymatic preparative scale. Regioselectivites of the methyltransferases were dependent on the group at C-1 and presence of fluorine in the THIQs. An interesting dual activity was also discovered for the catechol methyltransferases used, which were found to be able to regioselectively methylate two different catechols in a single molecule.
- Andexer, Jennifer N.,Cárdenas-Fernández, Max,Hailes, Helen C.,Méndez-Sánchez, Daniel,Richter, Michael,Roddan, Rebecca,Siegrist, Jutta,Subrizi, Fabiana,Thair, Benjamin,Wang, Yu,Ward, John M.
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- Design and Use of de novo Cascades for the Biosynthesis of New Benzylisoquinoline Alkaloids
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The benzylisoquinoline alkaloids (BIAs) are an important group of secondary metabolites from higher plants and have been reported to show significant biological activities. The production of BIAs through synthetic biology approaches provides a higher-yielding strategy than traditional synthetic methods or isolation from plant material. However, the reconstruction of BIA pathways in microorganisms by combining heterologous enzymes can also give access to BIAs through cascade reactions. Most importantly, non-natural BIAs can be generated through such artificial pathways. In the current study, we describe the use of tyrosinases and decarboxylases and combine these with a transaminase enzyme and norcoclaurine synthase for the efficient synthesis of several BIAs, including six non-natural alkaloids, in cascades from l-tyrosine and analogues.
- Wang, Yu,Tappertzhofen, Nadine,Méndez-Sánchez, Daniel,Bawn, Maria,Lyu, Boyu,Ward, John M.,Hailes, Helen C.
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p. 10120 - 10125
(2019/06/27)
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- Compositions and methods for producing benzylisoquinoline alkaloids
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The present invention relates to host cells that produce compounds that are characterized as benzylisoquinolines, as well as select precursors and intermediates thereof. The host cells comprise one, two or more heterologous coding sequences wherein each of the heterologous coding sequences encodes an enzyme involved in the metabolic pathway of a benzylisoquinoline, or its precursors or intermediates from a starting compound. The invention also relates to methods of producing the benzylisoquinoline, as well as select precursors and intermediates thereof by culturing the host cells under culture conditions that promote expression of the enzymes that produce the benzylisoquinoline or precursors or intermediates thereof.
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Page/Page column 2; 4; 8
(2016/05/19)
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- Absolute stereochemical assignment of SCH 71450, a selective dopamine D4 receptor antagonist, through enantioselective epimer synthesis
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The absolute stereochemical assignment of SCH 71450, a selective dopamine D4 receptor antagonist, has been successfully confirmed through enantioselective epimer synthesis. An allyl substituent on the p-hydroxybenzyl group was demonstrated to be an appropriate protecting group for Noyori Ru-catalyzed asymmetric transfer hydrogenation of the imine derivative. The construction of the sugar moiety involved a β-glycosylation reaction assisted by neighboring group participation. By comparison with literature data, the absolute stereochemistry at the C-1 carbon on the tetrahydroisoquinoline core has been assigned the S configuration. Copyright
- Wu, Hsin-Pei,Lu, Tai-Ni,Hsu, Nai-Yun,Chang, Che-Chien
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p. 2898 - 2905
(2013/07/05)
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- The catalytic potential of Coptis japonica NCS2 revealed - Development and utilisation of a fluorescamine-based assay ETI
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The versatility and potential of a norcoclaurine synthase (NCS) from Coptis japonica NCS2 has been investigated, together with the development and application of a novel fluorescence-based high-throughput assay using nearly forty amines/aldehydes. The stereocontrol exerted by CjNCS2 on selected non-natural substrates has been determined, where the tetrahydroisoquinolines (THIAs) were formed as the (1S)-isomer in >95% ee, as observed with the natural product norcoclaurine. Docking calculations involving THIA mechanism intermediates, utilising the reported Thalictrum flavum NCS X-ray crystallographic structure, were carried out and combined with the CjNCS2 screening results to further understand the mode of action of NCS. These findings suggested that in addition to the key active-site residues K122 and E110, D141 is also mechanistically essential for the enzymatic transformation. The exceptional tolerance of NCS towards aldehyde substrates is furthermore supported by our proposed mechanism in which the aldehydes protrude out of the enzymatic pocket. Copyright
- Pesnot, Thomas,Gershater, Markus C.,Ward, John M.,Hailes, Helen C.
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p. 2997 - 3008
(2013/01/15)
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- Biocatalytic production of tetrahydroisoquinolines
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The promiscuity of the enzyme norcoclaurine synthase is described. This biocatalyst yielded a diverse array of substituted tetrahydroisoquinolines by cyclizing dopamine with various acetaldehydes in a Pictet-Spengler reaction. This enzymatic reaction may provide a biocatalytic route to a range of tetrahydroisoquinoline alkaloids.
- Ruff, Bettina M.,Br?se,O'Connor, Sarah E.
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supporting information; experimental part
p. 1071 - 1074
(2012/03/27)
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