Laboratory of
Computational Biochemistry

Phylogenetic Analysis of Plant Sesquiterpene Synthases

Authors: Brian Y. Chen, Ashley Young, Hugh B. Nicholas Jr., Alexander J. Ropelewski and Troy Wymore

Since there is a clear evolutionary relationship between the monoterpene, sesquiterpene, and diterpene synthase sequences, phylogenetic analysis has typically been focused at the superfamily level. Yet, because 1) the different classes of Terpene Synthases (TSs) bind substrates that differ by at least five carbons and 2) the lack of characterized plant sequences and 3) the rapid evolution of plant species, robust structure-function relationships have not emerged from such bioinformatics analyses. In this presentation, we will describe our efforts to characterize plant sesquiterpene synthases (STSs) that bind farnesyl diphosphate and then undergo a range of cyclization mechanisms to produce a variety of products. Our phylogenetic analyses of STSs reveal that sequences that carry out a common cyclization/mechanistic step in the catalytic cycle form distinct sub-groups within the tree. From these classifications and comparative protein structure modeling, specific residues have been identified that impact product distribution.