Lipoxygenases and Diversity in Oxylipin Biosynthesis

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Intellectual Merit: Oxylipins are signaling compounds that mediate an array of defense mechanisms in animals, plants, fungi and cyanobacteria. They are derived from polyunsaturated fatty acids and their synthesis is initiated by the action of enzymes known as lipoxygenases. The product of the lipoxygenase catalyzed reaction is further transformed to the active signaling molecule by the action of additional enzymes. The reaction catalyzed by lipoxygenase is remarkably precise: the enzyme is able to generate only one of a number of products possible in a non-enzymatic reaction. The research is aimed at providing a three-dimensional understanding of how different lipoxygenases can generate a distinct product from the same starting compound. In addition, lipoxygenases are often expressed as bi-functional proteins, i.e. the enzyme is fused to a second catalytic domain which further transforms the lipoxygenase product. Thus the chemical diversity of oxylipins in nature is further expanded. This research will reveal the catalytic machinery that produces the remarkable diversity of compounds produced by bi-functional lipoxygenases. Knowledge of the structural basis of the highly novel chemistries performed by this unique class of enzymes will provide the means to exploit mono and bi-functional lipoxygenases for the synthesis of natural products, or derivatives thereof, to produce pesticides and anti-fungals.Broader Impacts: The studies form an essential part of a long term commitment to the integration of research and education. While graduate students will primarily be responsible for execution of the research, undergraduates will continue to make important contributions to progress and students at all levels will gain broad exposure to both state-of-the-art techniques and an integrative approach to understanding biological processes at the molecular level. Understanding molecular mechanisms at a level that allows one to exploit the tools of nature to improve the world in which lives requires combining diverse approaches. While this need for an interdisciplinary effort has fueled what may be termed "team" science, such a training environment is not necessarily hospitable for young investigators as it can easily foster highly specialized training if their movement between sub-disciplines is not deemed cost effective. In the studies the PI and students work side by side to combine methods in structural biology, biochemistry and molecular biology to address aspects of structure/function relationships in key enzymes in oxylipin biosynthesis.