Redirecting tropane alkaloid metabolism reveals pyrrolidine alkaloid diversity in Atropa belladonna

Abstract

Summary Plant‐specialized metabolism is complex, with frequent examples of highly branched biosynthetic pathways, and shared chemical intermediates. As such, many plant‐specialized metabolic networks are poorly characterized. The N‐methyl Δ1‐pyrrolinium cation is a simple pyrrolidine alkaloid and precursor of pharmacologically important tropane alkaloids. Silencing of pyrrolidine ketide synthase (AbPyKS) in the roots of Atropa belladonna (Deadly Nightshade) reduces tropane alkaloid abundance and causes high N‐methyl Δ1‐pyrrolinium cation accumulation. The consequences of this metabolic shift on alkaloid metabolism are unknown. In this study, we utilized discovery metabolomics coupled with AbPyKS silencing to reveal major changes in the root alkaloid metabolome of A. belladonna. We discovered and annotated almost 40 pyrrolidine alkaloids that increase when AbPyKS activity is reduced. Suppression of phenyllactate biosynthesis, combined with metabolic engineering in planta, and chemical synthesis indicates several of these pyrrolidines share a core structure formed through the nonenzymatic Mannich‐like decarboxylative condensation of the N‐methyl Δ1‐pyrrolinium cation with 2‐O‐malonylphenyllactate. Decoration of this core scaffold through hydroxylation and glycosylation leads to mono‐ and dipyrrolidine alkaloid diversity. This study reveals the previously unknown complexity of the A. belladonna root metabolome and creates a foundation for future investigation into the biosynthesis, function, and potential utility of these novel alkaloids.

The first specific probe for pyrrolidine with multifunction by the interaction mechanism of atomic economic reaction

“…Response time is another important parameter of the probe real-time tracking target. 1 Therefore, we also evaluated the time dependence of the UV intensity change of probe 1 in the presence of PyD. The results show that the color of the solution of probe 1 changed significantly after adding PyD for 5 min and basically reached stability after 60 min ( Figure 4 D).…”

“…It is well-known that safety testing during the production, transportation, and use of bulk chemicals is a concern for everyone, not only including chemists. The structure unit of pyrrolidine (PyD) is widely found in many bio-active natural products 1 and drug candidates. 2 In fact, PyD is extensively used as an important synthon in organic synthesis.…”

The chromosome-scale genome and the genetic resistance machinery against insect herbivores of the Mexican toloache, Datura stramonium

“…This compound serves as the substrate for the synthesis of tropinone via the enzymatic activity of chalcone synthase, which was also connected with amine oxidase in our study ( Kanehisa and Goto 2000 ). Moreover, chalcone synthase was also associated with tropinone reductase I, an enzyme responsible for tropine production ( Kanehisa and Goto 2000 ; Dräger 2006 ; Parks et al 2023 ). Tropine serves as an intermediate substrate in the synthesis of atropine and scopolamine ( Richter et al 2005 ).…”