DBBS

Plants are amazing chemists capable of generating an array of small molecules with different biological effects. The goal of our research is to understand the molecular machinery involved in assembling these compounds. Currently, we are studying the biosynthesis of peptides that protect plants from heavy metal toxicity and environmental stresses using approaches that blend biochemistry, plant biology, and x-ray crystallography. Understanding how plants synthesize these peptides provides a foundation for engineering their production. For example, in Arabidopsis and other plants, phytochelatin synthase (PCS) catalyzes the formation of heavy metal chelating peptides. Recently, we re-engineered PCS using directed evolution methods to improve tolerance to cadmium and are evaluating the effect of expressing the engineered PCS on cadmium tolerance and accumulation in plants. Future work will explore the potential of this engineered system as a bioremediation tool. In a related project, we are examining glutathione biosynthesis in plants. Although glutathione is a key component in a plant’s stress response network, the structural and functional details of the proteins that synthesize it, as well as the potential biochemical mechanisms of their regulation, remain unexplored. Our initial investigations suggest that cellular redox environment regulates a key step in this pathway through a thiol-based switching mechanism. This work may lead to more general models of how redox environment regulates protein function in plants. We are also collaborating with Divergence, Inc. (St. Louis, MO) to mechanistically and structurally characterize new protein targets for the development of compounds targeting parasitic nematodes.

Lee SG, Haakenson W, McCarter JP, Williams DJ, Hresko MC, Jez JM (2011) Thermodynamic evaluation of ligand binding in the plant-like phosphoethanolamine methyltransferases of the parasitic nematode Haemonchus contortus. J. Biol. Chem. 2011 286: 38060-38068.
 
Alvarez S, Galant A, Jez JM, Hicks LM.  Redox-regulatory mechanisms induced by oxidative stress in Brassica juncea roots monitored by 2-DE proteomics. Proteomics 2011 11: 1346-1135.
 
Chen Q, Westfall CS, Hicks LM, Wang S, Jez JM.  Kinetic basis for the conjugation of auxin by a GH3 family indole acetic acid-amido synthetase. J. Biol. Chem. 2010 285: 29780-29786.
 
Schroeder AC, Zhu C, Yanamadala SR, Cahoon RE, Arkus KAJ, Wachsstock L, Bleeke J, Krishnan HB, Jez JM. Threonine-insensitive homoserine dehydrogenase from soybean: genomic organization, kinetic characterization, and in vivo activity. J. Biol. Chem.
2010 Jan 8;285(2):827-34. Epub 2009 Nov 6. 
Galant A, Arkus KAJ, Zubieta C, Cahoon RE, Jez JM. Structural basis for evolution of product diversity in soybean glutathione synthesis. Plant Cell 2009 21: 3450-3458.