The terpene indole alkaloids are a diverse group of molecules with a range of chemical structures and medicinal uses. Understanding the enzymes that catalyze natural product biosynthesis may enable production in more tractable host organisms, and may also allow reprogramming of biosynthetic pathways to produce """"""""unnatural"""""""" natural products with improved pharmacological activities. Our laboratory seeks to understand, and ultimately harness, the metabolic pathways that direct the biosynthesis of plant-derived terpene indole alkaloids. This proposal describes the use of the terpene indole alkaloid biosynthetic pathway to make novel alkaloid structures.
Specific Aim 1. The First Committed Step of Terpene Indole Alkaloid Biosynthesis This aim focuses on strictosidine synthase, the enzyme that catalyzes the first committed step of the terpene indole alkaloid biosynthetic pathway. The major focus of this aim is to understand and modify the substrate specificity of strictosidine synthase using rational and random mutagenesis. Synthesis of substrates, development of assays and design of mutants are described.
Aim 1 A Tryptamine Substrate Specificity Aim 1B Secologanin Substrate Specificity Aim 1C Altering Strictosidine Synthase Substrate Specificity Specific Aim 2. Later Steps in the Terpene Indole Alkaloid Pathway The substrate specificity of the second committed step of terpene indole biosynthesis, catalyzed by strictosidine glucosidase, will be examined. Precursor directed biosynthesis in C. roseus cell culture and plants are used to probe the substrate specificity of the later steps of the pathway. Alkaloid analogues are isolated and structurally characterized. Use of a substrate analogue to purify a later enzyme in the pathway is described.
Aim 2 A Substrate Specificity of Strictosidine Glucosidase Aim 2B Probing the Biosynthetic Pathway Specificity in vivo

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
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Synthetic and Biological Chemistry B Study Section (SBCB)
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Jones, Warren
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Massachusetts Institute of Technology
Schools of Arts and Sciences
United States
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Runguphan, Weerawat; O'Connor, Sarah E (2013) Diversification of monoterpene indole alkaloid analogs through cross-coupling. Org Lett 15:2850-3
Glenn, Weslee S; Runguphan, Weerawat; O'Connor, Sarah E (2013) Recent progress in the metabolic engineering of alkaloids in plant systems. Curr Opin Biotechnol 24:354-65
Ruff, Bettina M; Bräse, S; O'Connor, Sarah E (2012) Biocatalytic production of tetrahydroisoquinolines. Tetrahedron Lett 53:1071-1074
Geu-Flores, Fernando; Sherden, Nathaniel H; Courdavault, Vincent et al. (2012) An alternative route to cyclic terpenes by reductive cyclization in iridoid biosynthesis. Nature 492:138-42
Hicks, Michael A; Barber 2nd, Alan E; Giddings, Lesley-Ann et al. (2011) The evolution of function in strictosidine synthase-like proteins. Proteins 79:3082-98
Liscombe, David K; O'Connor, Sarah E (2011) A virus-induced gene silencing approach to understanding alkaloid metabolism in Catharanthus roseus. Phytochemistry 72:1969-77
Glenn, Weslee S; Nims, Ezekiel; O'Connor, Sarah E (2011) Reengineering a tryptophan halogenase to preferentially chlorinate a direct alkaloid precursor. J Am Chem Soc 133:19346-9
Giddings, Lesley-Ann; Liscombe, David K; Hamilton, John P et al. (2011) A stereoselective hydroxylation step of alkaloid biosynthesis by a unique cytochrome P450 in Catharanthus roseus. J Biol Chem 286:16751-7
Bernhardt, Peter; Usera, Aimee R; O'Connor, Sarah E (2010) Biocatalytic asymmetric formation of tetrahydro-?-carbolines. Tetrahedron Lett 51:4400-4402
Cheng, Johnathan Z; Coyle, Christine M; Panaccione, Daniel G et al. (2010) Controlling a structural branch point in ergot alkaloid biosynthesis. J Am Chem Soc 132:12835-7

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