Reinvestigation of the Proton Resonance Spectrum of Vindolinine at 300 MHz

Durham, Lois J.; Shoolery, James Ν.; Djerassi, Carl

doi:10.1073/pnas.71.10.3797

Cited by 10 publications

(2 citation statements)

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“…The identity of the two vindolinine epimers were confirmed by comparing to a commercial standard for 19R-vindolinine and Nuclear Magnetic Resonance (NMR) analyses of 19S-vindolinine purified from C. roseus leaf chloroform extract (Supplementary Fig. 1, Supplementary Table 1) 15,16 . The vindolinines are structurally related with the aspidosperma type MIA tabersonine, but differ by the addition of C2-C19 bridge and reduction of the C2-C16 double bonds (Fig.…”

Section: Resultsmentioning

confidence: 93%

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A Catharanthus roseus Fe(II)/α-ketoglutarate-dependent dioxygenase catalyzes a redox-neutral reaction responsible for vindolinine biosynthesis

et al. 2022

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The Madagascar’s periwinkle is the model plant for studies of plant specialized metabolism and monoterpenoid indole alkaloids (MIAs), and an important source for the anticancer medicine vinblastine. The elucidation of entire 28-step biosynthesis of vinblastine allowed further investigations for the formation of other remarkably complex bioactive MIAs. In this study, we describe the discovery and characterization of vindolinine synthase, a Fe(II)/α-ketoglutarate-dependent (Fe/2OG) dioxygenase, that diverts assembly of tabersonine to vinblastine toward the formation of three alternatively cyclized MIAs: 19S-vindolinine, 19R-vindolinine, and venalstonine. Vindolinine synthase catalyzes a highly unusual, redox-neutral reaction to form a radical from dehydrosecodine, which is further cyclized by hydrolase 2 to form the three MIA isomers. We further show the biosynthesis of vindolinine epimers from tabersonine using hydrolase 2 catalyzed reverse cycloaddition. While the occurrence of vindolinines is rare in nature, the more widely found venalstonine derivatives are likely formed from similar redox-neutral reactions by homologous Fe/2OG dioxygenases.

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Section: Resultsmentioning

confidence: 93%

“…They also differ from each other by the C19 stereochemistry, resulting in 0.4 ppm chemical shift difference for H18 (Supplementary Fig. 1) 15,16 . In addition to the two vindolinines, we were also able to detect and purify venalstonine from the same chloroform extract and confirmed its identity by NMR (Supplementary Fig.…”

Section: Resultsmentioning

confidence: 99%