Biology subjects

Ploss, K.

Publications and source records attributed to Ploss, K..

3 recordsLinked to original sources

bioRxiv2025

BAHD news from Euphorbia peplus: identification of acyltransferase enzymes involved in ingenane diterpenoid biosynthesis

O_LIThe plant family Euphorbiaceae are an abundant source of structurally complex diterpenoids, many of which have reported anti-cancer, anti-HIV, and anti-inflammatory activities. Among these, ingenol-3-angelate (1a; tradename: Picato(R)), isolated from Euphorbia peplus, has potent anti-tumour activity. C_LIO_LIHere we report the discovery and characterization of the first genes linked to the committed steps of ingenol-3-angelate (1a) biosynthesis in Euphorbia peplus. We identified two genes, the products of which catalyse the addition of angelyl-CoA (9a) to the ingenol (5) scaffold to produce ingenol-3-angelate (1a). C_LIO_LIWe demonstrate using VIGS that just one of these genes, EpBAHD-08, is essential for this angeloylation in E. peplus. VIGS of the second gene, EpBAHD-06, has a significant effect on jatrophanes rather than ingenanes in E. peplus. C_LIO_LIWe also identified three genes whose products can catalyse acetylation of ingenol-3-angelate (1a) to ingenol-3-angelate-20-acetate (2). In this case VIGS indicates considerable functional redundancy in the E. peplus genome of genes encoding this enzymatic step. C_LIO_LIThis work paves the way for increasing ingenol-3-angelate (1a) levels in planta and provides a foundation for the discovery of the remaining genes in the biosynthetic pathway of these important molecules. C_LI

biochemistry↗

bioRxiv2024

Biosynthetic Origin of the Methoxy Group in Quinine and Related Cinchona Alkaloids

Quinine is a historically important natural product containing a methoxy group that is assumed to be incorporated at a late pathway stage. Here we show that the methoxy group in quinine and related Cinchona alkaloids is introduced onto the starting substrate tryptamine. Feeding studies with Cinchona plantlets definitively show that 5-methoxytryptamine is utilized as a quinine biosynthetic intermediate in planta. We discover the biosynthetic genes that encode the responsible oxidase and methyltransferase, and we use these genes to reconstitute the early steps of the Cinchona alkaloid biosynthetic pathway in Nicotiana benthamiana to produce a mixture of methoxylated and desmethoxylated Cinchona alkaloid intermediates. Importantly, we show that the co-occurrence of both tryptamine and 5-methoxytryptamine substrates, along with the substrate promiscuity of downstream pathway enzymes, enable parallel formation of both methoxylated and desmethoxylated alkaloids in Cinchona pubescens.

plant biology↗

bioRxiv2024

Independent evolution of ipecac alkaloid biosynthesis

Ipecac alkaloids are medicinal monoterpenoid-derived tetrahydroisoquinoline alkaloids found in two distantly related plants: Carapichea ipecacuanha (Gentianales) and Alangium salviifolium (Cornales). We have elucidated ipecac alkaloid biosynthesis in both species, conclusively demonstrating that biosynthesis of the structurally complex ipecac alkaloid protoemetine has evolved independently. We show that although protoemetine biosynthesis proceeds via the same chemical logic in both species, each plant uses a distinct monoterpene precursor. Moreover, we provide evidence that both plants initiate ipecac biosynthesis by a non-enzymatic Pictet-Spengler reaction, and we elucidate the biosynthetic fate of both the 1R and 1S stereoisomers that are produced in this non-stereoselective reaction. Phylogenetic analyses clearly show independent pathway evolution through parallel and convergently evolved enzymes. This work provides insight into how nature can capitalize on highly reactive starting substrates, the manner in which multi-step pathways can arise, and also lays the foundation for metabolic engineering of these important medicinal compounds.

plant biology↗