Student Speaker

Playing in the Pines: Exploring the Evolutionary Landscape of Conifer Resin Synthases

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Abstract

One way to understand how enzymes can be manipulated and reengineered to produce distinct products is investigation of their evolutionary history. Deciphering how enzymatic activity was altered identifies key residues, and how these impact catalysis. An E. Coli Metabolic engineering system was used to identify products from reconstructed ancestors of gymnosperm resin diterpene synthases, along with site-directed mutagenesis to investigate potential evolutionary pathways. Previous results have shown that the ancestral activity of Pinaceae diterpene synthases is the production of abietaenol, however, the three major lineages (spruce, fir, and pine) also produce isopimaradiene using diterpene synthases that evolved independently in each. Based on identification of the closely related isopimaradiene and abietaenol synthases from spruce, our lab has shown a single residue switch, specifically replacement of an alanine with a serine, changes product outcome in the spruce abietaenol synthase to isopimaradiene. We hypothesized ancient Pinaceae could use this alanine to serine switch to produce isopimaradiene. However, our results indicate that this single residue switch is only effective in more recent ancestors.