Dr Benjamin Lichman

Plants are incredible chemical factories, capable of producing a host of complex molecules that synthetic chemists struggle to produce. These compounds are produced by plants as a way to interact with their environment, typically to attract or repel other organisms. Such molecules also have great significance for humans, as we use them for fragrances, agrichemicals and, most importantly, medicines. My general research interests lie in understanding how plants control the production of these valuable compounds, and then using this knowledge to produce natural products and novel chemicals in microbial or plant based platforms.

The iridoids are a family of monoterpenes found in a wide range of plant species. Iridoid compounds have been shown to have bioactive properties such as anticancer and antimicrobial activities. Iridoid biosynthesis also contributes one half of the monoterpene indole alkaloid scaffold, a large diverse family of compounds which include the anticancer agents vincristine and vinblastine, and widely recognised compounds such as quinine and strychnine. I am currently focussed on two aspects of iridoid biosynthesis: biochemical characterisation and enzyme discovery. I am attempting to understand the full biochemical details of key early steps in iridoid biosynthesis, including substrate channelling and protein-protein interactions. Progress in this area will impact on the metabolic engineering of microbes or plants for iridoid/alkaloid production—yields of valuable products can be increased through a full understanding of the natural plant systems. The second area of focus is enzyme discovery. By obtaining enzymes responsible for the chemical diversity of the iridoids and alkaloids, we will be able to produce a wide variety of compounds in metabolically engineered host organisms. I am looking for novel iridoid biosynthesis enzymes in the mint family (Lamiaceae) and am currently on the hunt for the enzyme involved in nepetalactone biosynthesis, the key bioactive ingredient in catnip and catmint (Nepeta sp).

I am currently undertaking training in molecular evolution and phylogenetics with the aim of taking the principles of evolution into synthetic biology. I hope that this will reveal new methods of optimising and editing synthetic biology systems and devices. I am also involved in outreach in schools, where I talk to students about scientific research including the exciting developments in synthetic biology.

Figure 1. Key early steps include hydroxylation of geraniol, then double oxidation of 8-hydroxy­geraniol by an alcohol dehydroge­nase (ADH). The key cyclisation re­action to nepetalactol is catalysed by iridoid synthase (ISY). Iridoids are commonly combined with oth­er pathways: with sugars to form glycosides and with tryptamine to form monoterpene indole alka­loids.

Figure 1. Key early steps include hydroxylation of geraniol, then double oxidation of 8-hydroxy­geraniol by an alcohol dehydroge­nase (ADH). The key cyclisation re­action to nepetalactol is catalysed by iridoid synthase (ISY). Iridoids are commonly combined with oth­er pathways: with sugars to form glycosides and with tryptamine to form monoterpene indole alka­loids.