The in cell structure and function of an intrinsically disordered plant stress protein

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Because plants are unable to move, they have developed several mechanisms to survive abiotic stresses such as cold and drought. With anthropogenic global warming these stresses are likely to become more frequent and more unpredictable. Our research proposal centers on understanding the structure and function of dehydrins (dehydration proteins). Genetic and protein expression studies have shown that dehydrins are essential for plants to survive these abiotic stresses. The mechanisms by which these proteins function has not yet been fully elucidated. Part of the issue is that dehydrins are highly hydrophilic proteins, which makes them intrinsically disordered. Because of this, they do not follow the standard paradigm that a protein needs to have a well-defined structure and have specific interactions with a ligand in order to have a biological function. A major part of our proposal is to use in cell NMR to examine the structure and function of a minimal (K2 dehydrin) and model (YSK2 dehydrin) from Vitis riparia (wild grape). This will require the use of cell-penetrating peptides in order to get the isotopically labelled protein inside the grape cell. The results will capture the structure and behaviour of an intrinsically disordered protein in its native environment. We will also dissect dehydrin's role in the binding and protection of DNA from damage caused by reactive oxygen species, which are formed during cold and drought. Our understanding of the protective roles of dehydrins on enzymes will be expanded by determining the mechanism by which these protective proteins function during dehydration. We will also use the power of bioinformatics to examine the conservation of dehydrin sequences, a non-trivial problem given that intrinsically disordered protein sequences evolve at a much faster rate due to reduced structural constrains. Related to this, we will also examine the evolution of dehydrins and test our hypothesis that they evolved as a frameshift mutation of an ordered stress-response protein.