Heterologous Systems and Kinetic Modeling to Study the Molecular Mechanism of Mevalonate Transport and Utilization in Yeast

Abstract

Isoprenoids are a useful class of natural products that are desirable to produce in microbial platforms. The objective of this thesis was to address two pertinent challenges with the genetic engineering of organisms for isoprenoid synthesis. First, mevalonate, which is a crucial precursor to isoprenoid production in eukaryotes, has been shown to be irreversibly exported from S. cerevisiae when its production pathway is overexpressed, hindering its utilization in downstream pathways. Thus, I sought to identify a heterologous transporter of mevalonate that could allow for its reuptake in these situations and considered two host organisms for this purpose, Y. lipolytica and E. coli. The second challenge involves understanding the behavior and optimal expression levels of IDI1 and ERG20, two enzymes immediately downstream of the mevalonate pathway necessary for the production of most isoprenoids, which I approached by developing a computational kinetic model of this reaction system that recreates trends seen from in vivo data.