Evolution of enzymes involved in fatty acid biosynthesis
Insect species use pheromones composed of different secondary metabolites for mate finding and mating. Pheromones are specific mixtures of saturated and unsaturated fatty acid (FA)-derived alcohols, aldehydes, esters, hydrocarborns, and epoxides and contribute to evolutionary success. Subtle changes in pheromone composition can represent the origin of new species evolution. The overall goal of this work is to uncover molecular mechanisms for the evolution of pheromone components. We focus on classes of enzymes involved in fatty acyl derivative biosynthesis, such as membrane fatty acyl desaturases (mFADs) and fatty acyl reductases (FARs). mFADs introduce double bonds into FA hydrocarbon chains, and FARs reduce fatty-acyl CoA to fatty alcohols. As model species, we use the tobacco hornworm moth, Manduca sexta (Lepidoptera), and the bumblebees Bombus terrestris, Bombus lucorum, and Bombus lapidarius.
We have found that a single amino acid substitution in the kink of the mFAD substrate binding tunnel can lead to synthesis of novel unsaturated FA precursors. Currently, our project is focused on confirming this mechanism of FAD specificity determination and understanding the evolution of new pheromone components and new insect species.
Novel results obtained from analysis of FAR gene expression profiles in pheromone glands of three bumblebee species indicate that these insects possess a separate class of FARs. We are working to characterize these enzymes and determine the structural motifs critical for their functions.
These projects are done in collaboration with Irena Valterová from IOCB and Aleš Svatoš from the Max Planck Institute for Chemical Ecology in Jena, Germany. Our manuscript “Evolution of moth sex pheromone composition by a single amino acid substitution in a fatty acid desaturase,” published in PNAS in 2015, inspired René Levinski’s theatre performance “Press Space to Continue,” which is currently on the program of the New Stage of the National Theatre in Prague and the City Theatre of Brno.