Environmental stresses result in considerable losses in crop quality and plant biomass productivity. Exposure of plants to temperature extremes, drought, pollution, and pathogens results in the generation of reactive oxygen species that alter signaling pathways and growth. As part of their response to these stresses, plants produce the peptide glutathione. Glutathione acts as an antioxidant by quenching reactive oxygen species and is essential for the detoxification of environmental pollutants. Two enzymes catalyze glutathione synthesis: glutamate-cysteine ligase (GCL), and glutathione synthetase (GS). This project explores how these enzymes function and are regulated by 1) examining the structure of plant GS, 2) establishing the role of GCL as a regulatory switch in glutathione biosynthesis; and 3) identifying additional plant proteins that act as redox-linked regulatory switches. Efforts related to broader impact fall into two categories. First, the research project provides undergraduate and graduate students with multidisciplinary training in plant biology, biochemistry, and structural biology. At the graduate level, two students are involved in the project. At the undergraduate level, both the PI and Co-PI are active in the NSF-REU program at the Danforth Center and in the Pfizer-Solutia Summer Students and Teachers as Research Scientists (STARS) program. Second, the PI helped develop an upper-level undergraduate/graduate plant biology course (Bio4024) at Washington University that offers research-based experiments that combine protein chemistry, x-ray crystallography, mass spectrometry/proteomics, and microscopy (Jez et al., 2007 Biochem. Mol. Biol. Educ. 35, 410-415). By blending biochemistry and plant biology, students acquire the breadth of understanding and the scientific skills required for solving problems at the interface of these disciplines.
