PLANT SCIENCE

Missing enzymes in the biosynthesisof the anticancer drug vinblastinein Madagascar periwinkleLorenzo Caputi1, Jakob Franke1*, Scott C. Farrow1, Khoa Chung1,Richard M. E. Payne1†, Trinh-Don Nguyen1, Thu-Thuy T. Dang1,Inês Soares Teto Carqueijeiro2, Konstantinos Koudounas2,Thomas Dugé de Bernonville2, Belinda Ameyaw1‡, D. Marc Jones1,Ivo Jose Curcino Vieira3, Vincent Courdavault2§, Sarah E. O’Connor1§

Vinblastine, a potent anticancer drug, is produced by Catharanthus roseus (Madagascarperiwinkle) in small quantities, and heterologous reconstitution of vinblastine biosynthesiscould provide an additional source of this drug. However, the chemistry underlyingvinblastine synthesis makes identification of the biosynthetic genes challenging. Herewe identify the two missing enzymes necessary for vinblastine biosynthesis in thisplant: an oxidase and a reductase that isomerize stemmadenine acetate intodihydroprecondylocarpine acetate, which is then deacetoxylated and cyclized to eithercatharanthine or tabersonine via two hydrolases characterized herein. The pathways showhow plants create chemical diversity and also enable development of heterologousplatforms for generation of stemmadenine-derived bioactive compounds.

Anticancer drugs vincristine 5 and vinblas-tine 6 were discovered 60 years ago inCatharanthus roseus (Madagascar periwin-kle). These compounds have been used forthe treatment of several types of cancer,

including Hodgkin’s lymphoma, as well as lungandbrain cancers.Much of themetabolic pathway(31 steps from geranyl pyrophosphate to vinblas-tine) has been elucidated (1–3). Here we reportthe genes encoding the missing enzymes thatcomplete the vinblastine pathway. Two redoxenzymes convert stemmadenine acetate 7 intoan unstable molecule, likely dihydroprecondy-locarpine acetate 11,which is thendesacetoxylatedby one of two hydrolases to generate, throughDiels-Alder cyclizations, either tabersonine 2 orcatharanthine 3 scaffolds that are ultimatelydimerized to yield vinblastine and vincristine(Fig. 1A). In addition to serving as the precursorsfor vincristine 5 and vinblastine 6, tabersonine 2and catharanthine 3 are also precursors for otherbiologically active alkaloids (4, 5) (Fig. 1B). Thediscovery of these two redox enzymes (precon-dylocarpine acetate synthase and dihydroprecon-dylocarpine acetate synthase), along with thecharacterization of two hydrolases (tabersonine

and catharanthine synthase), provides insightinto the mechanisms that plants use to createchemical diversity and also enables productionof a variety of high-value alkaloids.Catharanthine 3 (iboga-type alkaloid) and

tabersonine 2 (aspidosperma-type) scaffolds arelikely generatedbydehydration of the biosyntheticintermediate stemmadenine 1 to dehydrosecodine9, which can then cyclize to either catharanthine3or tabersonine 2 via a net [4+2] cycloadditionreaction (Fig. 2) (6–9). We speculated that themissing components were an enzyme with dehy-dration and cyclization function.We hypothesizedthat the unstable nature of the dehydration pro-duct dehydrosecodine 9 (7) would preclude its dif-fusion out of the enzyme active site, and we thussearched for an enzyme that could catalyze bothdehydration and cyclization reactions.Because the biosynthetic genes for vincristine 5

and vinblastine 6 are not clustered in the plantgenome (10), we searched for gene candidates inRNA sequencing (RNA-seq) data (10) from thevincristine- and vinblastine-producing plantC. roseus. Two genes annotated as alpha/betahydrolases were identified by a shared expressionprofile with previously identified vinblastine bio-synthetic enzymes (fig. S1A and data S1). A dehy-dratase could facilitate the isomerization of the19,20-exo-cyclic double bond of stemmadenine1 to form iso-stemmadenine 8 (Fig. 2), whichwould then allow dehydration to form dehydro-secodine 9 and, consequently, catharanthine andtabersonine (8). Virus-induced gene silencing(VIGS) of herein-named tabersonine synthase(TS) and catharanthine synthase (CS) (Fig. 1 andfigs. S2 and S3) in C. roseus resulted in a markedreduction of tabersonine 2 (P= 0.0048) andcatharanthine (P = 0.01), respectively. These si-lencing experiments implicate CS and TS in

catharanthine 3 and tabersonine 2 biosynthesisin C. roseus. However, when CS and TS were het-erologously expressed inEscherichia coli (fig. S4A)and tested for reactivity with stemmadenine1 (fig. S5) or the acetylated form of stemmade-nine 7 (fig. S6), in which spontaneous defor-mylation would be hindered (Fig. 2, figs. S5 andS6, and tables S4 and S5), no reaction was ob-served. Although TS and CS are known to beimplicated in vinblastine biosynthesis (11), thesubstrates, and therefore the specific catalyticfunctions, remained elusive.We used enzyme-assay guided fractionation in

an attempt to isolate the active substrate for theTS and CS enzymes from various aspidosperma-alkaloid– and iboga-alkaloid–producing plants.We focused on Tabernaemontana plants thatare known to accumulate more stemmadenine1 intermediate relative to downstream alkaloids(12). These experiments demonstrated that TSandCSwere always activewith the same fractions(fig. S7), consistent with previous hypotheses (6)that both enzymes use the same substrate. How-ever, attempts to structurally characterize thesubstrate were complicated by its rapid decompo-sition, and the deformylated product tubotaiwine12 [previously synthesized in reference (13)] wasthe major compound detected in the isolatedmixture [Fig. 2 and nuclear magnetic resonance(NMR) data in fig. S8]. Given the propensity fordeformylation in these structural systems (14),we rationalized that tubotaiwine 12 could be thedecomposition product of the actual substrate,which would correspond to iso-stemmadenine 8(dihydroprecondylocarpine) or its protected form(dihydroprecondylocarpine acetate 11) (Fig. 2).We surmised that a coupled oxidation-reductioncascade could perform a net isomerization togenerate dihydroprecondylocarpine 8 (or dihy-droprecondylocarpine acetate 11) from stem-madenine 1 (or stemmadenine acetate 7). Thisidea was initially proposed by Scott and Wei,who indicated that stemmadenine acetate 7can be oxidized to precondylocarpine acetate 10,after which the 19,20-double bond can then bereduced to form dihydroprecondylocarpine ace-tate 11, which can then form traces of tabersonine2 upon thermolysis (15). Similar reactions withstemmadenine 1 resulted indeformylation to formcondylocarpine 13 (16). Therefore, we reexaminedthe RNA-seq dataset for two redox enzymes thatcould convert stemmadenine acetate 7 to dihy-droprecondylocarpine acetate 11.We noted a gene annotated as reticuline oxi-

dase that had low absolute expression levels buta similar tissue expression pattern to that of theTS gene (fig. S1B). The chemistry of reticulineoxidase enzymes (17) such as berberine bridgeenzyme and dihydrobenzophenanthridine oxi-dase suggests that these enzymes are capableof C–N bond oxidation, which would be requiredin this reaction sequence (Fig. 2) (17). When thisoxidase genewas silenced in C. roseus, a compoundwith a mass and 1H NMR spectrum correspondingto semisynthetically prepared stemmadenineacetate 7 (the proposed oxidase substrate) accu-mulated, suggesting that this gene encoded the

RESEARCH

Caputi et al., Science 360, 1235–1239 (2018) 8 June 2018 1 of 4

1Department of Biological Chemistry, John Innes Centre,Norwich Research Park, Norwich NR4 7UH, UK. 2Universitéde Tours, EA2106 Biomolécules et BiotechnologiesVégétales, Parc de Grandmont 37200 Tours, France.3Laboratorio de Ciencias Quimicas-UENF-Campos dosGoytacazes-RJ, 28013-602, Brazil.*Present address: Centre of Biomolecular Drug Research, LeibnizUniversity Hannover, Schneiderberg 38, 30167 Hannover, Germany.†Present address: Department of Biochemistry, University ofOxford, South Parks Road, Oxford OX1 3QU, UK.‡Present address: Department of Biology, University of Lancaster,Bailrigg, Lancaster LA1 4YW, UK.§Corresponding author. Email: sarah.oconnor@jic.ac.uk (S.E.O.);vincent.courdavault@univ-tours.fr (V.C.)

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correct oxidase. We named this enzyme precon-dylocarpine acetate synthase (PAS) (figs. S9 to S11).Similarly, silencing of a medium-chain alcoholdehydrogenase, as part of an ongoing screen ofalcohol dehydrogenases in C. roseus (14, 18, 19),

resulted in accumulation of a compound with amass, retention time, and fragmentation patternconsistent with a partially characterized syntheticstandard of precondylocarpine acetate 10 (theproposed substrate of the reductase) (figs. S12

to S14). This standard could be synthesized fromstemmadenine acetate 7 using Pt and O2 by es-tablished methods (8, 15, 20). With our small-scale reactions, yields were low and variable, andthe product decomposed during characterization.

Caputi et al., Science 360, 1235–1239 (2018) 8 June 2018 2 of 4

Fig. 1. Vincristine and vinblastine biosynthesis. (A) Vincristine 5 andvinblastine 6 are formed by dimerization from the monomers catharanthine 3and vindoline 4 by a peroxidase (28) or chemical methods (29). The

genes that convert tabersonine 2 to vindoline 4 have been identified(24). (B) Representative bioactive alkaloids derived from stemmadenine.Me, methyl; Et, ethyl.

N

CO2Me

H

NH

N

CO2MeNH

N

CO2MeNH

NH

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CO2Me

dienedienophile

NH

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CO2Me

OH

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PASorii.

DPAS

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OH

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21

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H3

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3

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CO2MeOAc

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NMR, HRMSpartial NMR, HRMS

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iso-stemmadenine 8

dehydrosecodine 9

catharanthine 3 tabersonine 2

stemmadenine 1 stemmadenine acetate 7 precondylocarpine acetate (open) 10

precondylocarpine acetate (closed) 10

condylocarpine 13

tubotaiwine 12dihydroprecondylocarpineacetate (open enamine) 11

dihydroprecondylocarpine acetate (open) 11

dihydroprecondylocarpine acetate (closed) 11

net isomerization

19

21

OAc

Fig. 2. Biosynthesis of catharanthine and tabersonine scaffolds.Stemmadenine acetate 7 {generated from stemmadenine 1 under condition i[Ac2O (excess) and pyridine (excess) at room temperature (r.t.), 4 hours,>99% yield]} undergoes an oxidation to form precondylocarpine acetate 10.This reaction is catalyzed enzymatically by the reticuline oxidase homologPAS or, alternatively, can be generated synthetically under condition ii[Pt (from 7.5 equivalents of PtO2), EtOAc, O2 atmosphere, r.t., 10 hours,yields varied], as reported by Scott and Wei (8). Next, the open form of

precondylocarpine acetate 10 is reduced by the alcohol dehydrogenaseDPAS. This reduced intermediate could not be isolated due to its lability but,on the basis of degradation product tubotaiwine 12, is assumed to bedihydroprecondylocarpine acetate 11. Dihydroprecondylocarpine acetate 11, inthe open form, can form dehydrosecodine 9 through the action of CS orTS to form catharanthine 3 or tabersonine 2, respectively. Numbers withinstructures indicate different carbon atoms. spont., spontaneous; HRMS,high-resolution mass spectrometry; MS/MS, tandem mass spectrometry.

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However, the limited two-dimensional NMRdataset was consistent with an assignment ofprecondylocarpine acetate 10. Thus, we renamedthis alcohol dehydrogenase dihydroprecondy-locarpine synthase (DPAS). Collectively, thesedata suggest that PAS and DPAS act in concertwith CS or TS to generate catharanthine 3 andtabersonine 2.To validate whether these enzymes produce

catharanthine3 and tabersonine2, we transientlycoexpressed PAS, DPAS, and CS or TS in thepresence of stemmadenine acetate 7 inNicotianabenthamiana. These experiments illustrated thesequential activity of thenewlydiscoveredenzymes,whereby we observed formation of catharanthine3 in plant tissue overexpressing PAS, DPAS, andCS or tabersonine 2 in plant tissue overexpress-ing PAS, DPAS, and TS, when the leaf was also co-infiltrated with stemmadenine acetate 7 (Fig. 3A).The presence of all proteins was validated by pro-teomics analysis (fig. S4B and data S2). Formationof precondylocarpine acetate 10 was observed

when stemmadenine acetate 7 was infiltratedinto N. benthamiana in the absence of any het-erologous enzymes (Fig. 3A), suggesting that anendogenous redox enzyme(s) of N. benthamianacan oxidize stemmadenine acetate 7. Formationof 3 and 2 was validated by coelution with com-mercial standards, and formation of 10 wasvalidated by coelution with the semisyntheticcompound.Purified proteins were required to validate the

biochemical steps of this reaction sequence invitro. Whereas CS, TS, and DPAS all expressed insoluble form in E. coli (fig. S4A), the flavin-dependent enzyme PAS failed to express instandard expression hosts such as E. coli orSaccharomyces cerevisiae. To overcome this ob-stacle, we expressed the native full-length PAS inN. benthamiana plants using a transient expres-sion system (fig. S4B) in Pichia pastoris (fig. S4, Cand D) and in Sf9 insect cells (fig. S4E). The pres-ence of PAS was validated by proteomic data(data S3). Reaction of PAS from each of these

expression hosts with stemmadenine acetate 7produced a compound that had an identicalmass and retention time to our semisyntheticstandard of precondylocarpine acetate 10 (figs. S15and S16). The enzymatic assays with PAS proteinderived fromP. pastoris and Sf9 insect cells ensurethat formation of the expected products is not theresult of a protein contaminant found in theplant-expressed PAS protein. When the PAS pro-teins (from N. benthamiana and P. pastoris),along with stemmadenine acetate 7, were com-bined with heterologous DPAS and CS, cathar-anthine 3was formed, and when combined withDPAS and TS, tabersonine 2 was observed (figs.S17 and S18).Semisynthetic precondylocarpine acetate 10

could be reactedwithDPAS and TS or CS to yieldtabersonine 2 or catharanthine 3, respectively(fig. S19). In addition, a crude preparation of whatis proposed to be dihydroprecondylocarpineacetate 11, synthesized according to Scott andWei (8), was converted to catharanthine 3 and

Caputi et al., Science 360, 1235–1239 (2018) 8 June 2018 3 of 4

Fig. 3. Biosynthesis of tabersonine 2 and catharanthine 3 from stem-madenine acetate 7 starting substrate. (A) Reconstitution of tabersonine2 and catharanthine 3 in N. benthamiana from stemmadenine acetate7. Extracted ion chromatograms (XIC) for ions with mass/charge ratio(m/z) 397.19 (stemmadenine acetate 7),m/z 395.19 (precondylocarpineacetate 10), andm/z 337.19 [catharanthine at retention time (RT) 4.0 min andtabersonine at RT 4.4 min] are shown. EV, empty vector. (B) Interaction ofCS and TS with DPAS by bimolecular fluorescence complementation (BiFC) in

C. roseus cells.The efficiencyof BiFC complex reformation reflected by the YFPfluorescence intensity highlighted that CS and DPAS exhibited weakinteractions (i to iii), whereas TS and DPAS strongly interacted (iv to vi). Nointeractions with loganic acid methyltransferase (LAMT) were observed(vii to ix). YN,YFP N-terminal fragment; YC,YFP C-terminal fragment; nuc-CFP,nuclear cyan fluorescent protein; DIC, differential interference contrast.Scale bars, 10 mm. (C) Phylogenetic relationship of PAS with other functionallycharacterized berberine bridge enzymes.

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tabersonine 2 by the action of CS and TS, re-spectively (fig. S20). Reaction of PAS (purifiedfrom N. benthamiana) and DPAS with stemma-denine acetate 7 in the absence of CS or TS yieldeda compound isomeric to tabersonine 2 andcatharanthine 3, suggesting that cyclization canoccur spontaneously under these reaction condi-tions (fig. S17). As observed during attempts to pu-rify the CS or TS substrate from Tabernaemontanaplants, dihydroprecondylocarpine acetate 11 canalso deformylate to form tubotaiwine 12. Solventand reaction conditions probably determine howthe reactive dihydroprecondylocarpine acetate 11decomposes.PAS failed to react with stemmadenine 1, in-

dicating that the enzyme recognized the acetyl(Ac) group (fig. S21). Oxidation of stemmadenine1 produced a compound with a mass consistentwith that of the shunt product condylocarpine13. This identification was supported by com-parison of the tandem mass spectrometry spec-trum of 13 to that of the related compoundtubotaiwine 12 (fig. S22). The transformation ofstemmadenine 1 to condylocarpine 13 is known(15, 21). We therefore suspect that the acetylationof stemmadenine 1 is necessary to slow sponta-neous deformylation after oxidation, and AcOHserves as a leaving group to allow formation ofdehydrosecodine 9 (20). Acetylation also func-tions as a protecting group in the biosynthesisof noscapine in opium poppy (22).The reactivity of the intermediates involved in

the transformation of stemmadenine acetate 7 tocatharanthine 3 or tabersonine 2 suggests thatPAS, DPAS, and CS or TS should be colocalizedbecause the unstable post–precondylocarpineacetate 10 intermediates may not remain intactduring transport between cell types or compart-ments. Using yellow fluorescent protein (YFP)–tagged proteins in C. roseus cell suspensionculture, we showed that PAS is targeted to thevacuole through small vesicles budding from theendoplasmic reticulum (ER), as was previouslyobserved for the PAS homolog, berberine bridgeenzyme (23) (fig. S23). This localization suggeststhat stemmadenine acetate 7 oxidation occurs inthe ER lumen, ER-derived vacuole-targeted ves-icles, and/or vacuole. In contrast, colocalizationof DPAS, CS, and TSwas confirmed in the cytosol(figs. S24 and S25). Bimolecular fluorescence com-plementation suggested preferential interactionsbetween DPAS and TS (Fig. 3B and figs. S26 andS27). Such interactions may not only preventundesired reactions on the reactive dihydropre-condyocarpine acetate 11 intermediate but mayalso control the flux of 11 into tabersonine 2.Homologs of PAS are used throughout benzyl-

isoquinoline and pyridine alkaloid biosynthesis.

Certain PAS mutations characterize the enzymesfound in aspidosperma-alkaloid– and iboga-alkaloid–producing plant clades (Fig. 3C). Forinstance, PAS lacks the His and Cys residuesinvolved in covalent binding of the FAD cofactor(fig. S28). We anticipate that these aspidosperma-associated PAS homologs populate the metabolicpathways for the wide range of aspidospermaalkaloids found in nature. DPAS is a medium-chain alcohol dehydrogenase, a class of enzymeswidely used in monoterpene indole alkaloid bio-synthesis (14, 18, 19, 24). We hypothesize that CSand TS may retain the hydrolysis function of theputative ancestor hydrolase enzyme (25) to allowformation of dehydrosecodine 9 from dihydro-precondylocarpine acetate 11. In principle, theformation of tabersonine 2 and catharanthine 3is formed via two different modes of cyclization,and dehydrosecodine9 can undergo two distinctDiels-Alder reactions (26) to form either cathar-anthine 3 or tabersonine 2 (Fig. 2).Herewe report the discovery of two enzymes—

PAS and DPAS—along with the discovery of thecatalytic function of two other enzymes—CS andTS (11)—that convert stemmadenine acetate 7 totabersonine 2 and catharanthine 3. Chemical in-vestigations of this system (6–8, 15), coupled withplant DNA sequence data, enabled discovery ofthe last enzymes responsible for the constructionof the tabersonine 2 or catharanthine 3 scaffolds.With the biosynthesis of stemmadenine acetate 7(11), this completes the biosynthetic pathway forvindoline4 and catharanthine3, compounds thatcanbeused to semisyntheticallyprepare vinblastine.Thesediscoveries allow theprospect of heterologousproduction of these expensive and valuable com-pounds in alternative host organisms, providinga new challenge for synthetic biology (27).

REFERENCES AND NOTES

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Can. J. Chem. 60, 1269–1278 (1982).8. A. I. Scott, C. C. Wei, Tetrahedron 30, 3003–3011 (1974).9. H. Mizoguchi, H. Oikawa, H. Oguri, Nat. Chem. 6, 57–64 (2014).10. F. Kellner et al., Plant J. 82, 680–692 (2015).11. Y. Qu et al., Proc. Natl. Acad. Sci. U.S.A. 115, 3180–3185

(2018).12. N. Petitfrere, A. M. Morfaux, M. M. Debray, L. Le Men-Olivier,

J. Le Men, Phytochemistry 14, 1648–1649 (1975).13. B. A. Dadson, J. Harley-Mason, J. Chem. Soc. D 1969, 665b

(1969).14. E. C. Tatsis et al., Nat. Commun. 8, 316 (2017).15. A. I. Scott, C. C. Wei, J. Am. Chem. Soc. 94, 8264–8265 (1972).16. A. I. Scott, Acc. Chem. Res. 3, 151–157 (1970).

17. N. G. H. Leferink, D. P. H. M. Heuts, M. W. Fraaije, W. J. H. van Berkel,Arch. Biochem. Biophys. 474, 292–301 (2008).

18. A. Stavrinides et al., Chem. Biol. 22, 336–341 (2015).19. A. Stavrinides et al., Nat. Commun. 7, 12116 (2016).20. A. I. Scott, in Recent Advances in Phytochemistry,

V. C. Runeckles, Ed. (Plenum Press, 1975), chap. 9, pp. 189–241.21. M. El-Sayed, Y. H. Choi, M. Frédérich, S. Roytrakul,

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(2015).23. A. Bock, G. Wanner, M. H. Zenk, Planta 216, 57–63 (2002).24. Y. Qu et al., Proc. Natl. Acad. Sci. U.S.A. 112, 6224–6229

(2015).25. N. Lenfant et al., Nucleic Acids Res. 41, D423–D429 (2013).26. E. M. Stocking, R. M. Williams, Angew. Chem. Int. Ed. 42,

3078–3115 (2003).27. A. Casini et al., J. Am. Chem. Soc. 140, 4302–4316 (2018).28. M. Sottomayor, A. Ros Barceló, Protoplasma 222, 97–105 (2003).29. H. Ishikawa et al., J. Am. Chem. Soc. 131, 4904–4916 (2009).

ACKNOWLEDGMENTS

We thank G. Saalbach of the John Innes Proteomics Centre forproteomics work, F. Kellner and F. Geu-Flores for early silencingresults with CS and TS, B. Lichman for discussions, P. O’Connorfor Tabernaemontana material, and R. Hughes andM. Franceschetti for preparing the modified TRBO vector.We also thank MRC PPU Reagents and Services for PAS expressionin insect cells. Funding: This work was supported by grants fromthe European Research Council (311363), BBSRC (BB/J004561/1)(S.E.O.), and the Région Centre-Val de Loire, France (CatharSISgrant and BioPROPHARM project–ARD2020) (V.C.). J.F.acknowledges DFG postdoctoral funding (FR 3720/1-1) and T.-T.T.D.(ALTF 239-2015) and S.C.F. (ALTF 846-2016) acknowledgeEMBO Long-Term Fellowships. K.K. acknowledges the FrenchEmbassy in Greece for a SSHN grant. R.M.E.P. was supported by aPh.D. studentship from BBSRC. Author contributions: L.C.characterized all proteins, purified substrates, and coordinatedall experiments; J.F. performed experiments with PAS anddeveloped chemical mechanisms and synthetic strategy; S.C.F.helped with candidate selection and VIGS and performed thequantitative polymerase chain reaction experiments; K.C.performed all semisynthetic transformations; R.M.E.P. performedinitial cloning and characterization of PAS; T.-D.N. expressed PASin P. pastoris; T.-T.T.D. performed reconstitution in N. benthamiana;B.A. performed cloning and silencing experiments; D.M.J. helpedto identify PAS and designed initial silencing constructs; I.J.C.V.purified stemmadenine; I.S.T.C., K.K., T.D.d.B., and V.C. performedlocalization and interaction studies; L.C. and S.E.O. wrote themanuscript; and S.C.F., J.F., K.C., and V.C. revised the manuscript.Competing interests: A patent on PAS and DPAS is currentlybeing filed. Data and materials availability: Sequence data forPAS (MH213134), DPAS (KU865331), CS (MF770512), and TS(MF770513) are deposited in GenBank and are also provided inthe supplementary materials. Transcriptome data used inthis study have already been published (see supplementarymaterials and http://medicinalplantgenomics.msu.edu/). Celllines used in this study will be made available uponrequest. Data supporting the findings of this study are availablewithin the article and the supplementary materials.

SUPPLEMENTARY MATERIALS

www.sciencemag.org/content/360/6394/1235/suppl/DC1Materials and MethodsFigs. S1 to S28Tables S1 to S7References (30–59)Data S1 to S3

5 March 2018; accepted 24 April 2018Published online 3 May 201810.1126/science.aat4100

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periwinkleMissing enzymes in the biosynthesis of the anticancer drug vinblastine in Madagascar

Jose Curcino Vieira, Vincent Courdavault and Sarah E. O'ConnorInês Soares Teto Carqueijeiro, Konstantinos Koudounas, Thomas Dugé de Bernonville, Belinda Ameyaw, D. Marc Jones, Ivo Lorenzo Caputi, Jakob Franke, Scott C. Farrow, Khoa Chung, Richard M. E. Payne, Trinh-Don Nguyen, Thu-Thuy T. Dang,

originally published online May 3, 2018DOI: 10.1126/science.aat4100 (6394), 1235-1239.360Science 

, this issue p. 1235Sciencevincristine biosynthesis, but also for understanding the many other biologically active alkaloids found throughout nature.long-standing question of how plant alkaloid scaffolds are synthesized, which is important not only for vinblastine and

now describe the biosynthetic genes and corresponding enzymes responsible. This resolves aet al.Caputi however, the mechanism by which the scaffolds of catharanthine and tabersonine are generated has been a mystery.plant-derived alkaloids catharanthine and vindoline. The enzymes that transform tabersonine into vindoline are known;

Vinblastine and vincristine are important, expensive anticancer agents that are produced by dimerization of theHow to make bioactive alkaloids

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MATERIALSSUPPLEMENTARY http://science.sciencemag.org/content/suppl/2018/05/02/science.aat4100.DC1

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