A synthetic biology approach to the production of terpenoids by pathway engineering.

Synthetic biology integrates biochemistry and genetic engineering to artificially design and manipulate biological systems in organisms with the aim of remodelling their metabolic pathways to change their function and behaviours. This project will use synthetic biology to engineer natural product biosynthetic pathways. Natural products belong to an extensive family of diverse organic molecules with in excess of 200, 000 discovered and extracted from various sources and their importance is emphasised by their significance to the pharmaceutical industry for over 60 years, delivering novel antibiotics, hormones and anti-tumour agents to the therapeutic drug repertoire. Over the last 25 years, one quarter of pharmaceuticals are isolated natural products, or designed based on their structure.

Of the various classes of natural product, the isoprene family comprises over 40,000 distinct compounds and engineering of their biosynthetic pathways has already led to biotechnologically significant routes to isoprene-derived pharmaeuticals such as taxol and artemisinin. All isoprenes are derived from IPP (isopentenyl diphosphate) and DMPP (dimethylallyl diphosphate) via intermediates such as geranyl diphosphate (C10), farnesyl diphosphate (C15) and geranylgeranyl diphosphate (C20). Downstream enzymes then catalyse a range of chemical modifications to cyclise, oxidise, reduce, isomerise and hydroxylate the prenyldiphosphate intermediates to generate the respective terpenoid products. The tolerant nature of these terpene synthases presents engineering opportunities, modifying the enzyme structure to either synthesise different products or provide a preference for a desired product.

This project will use synthetic biology methods to optimise precursor concentrations either by native pathway optimisation or transportation of a heterologous pathway, in combination with heterologous expression of specific terpene synthase enzymes such the promiscuous y-humulene synthase, followed by structural studies and rational engineering of terpene synthases to bias the formation of desired terpenes from single substrate compounds.