Plants are amazing chemists capable of generating an array of compounds with a range of biological activities. Understanding the biosynthesis of these compounds at a structural and mechanistic level is the foundation for manipulating their assembly either in vitro or in vivo. Our research employs biochemistry, protein engineering, and x-ray crystallography to investigate the molecular basis of biological processes in plants. We are currently focusing on the synthesis of molecules involved in protecting plants from heavy metal toxicity, including phytochelatins, glutathione, and cysteine (Figure 1).