Insight into freeze resistance and proteostasis from protective proteins and small organic molecules of marine species

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Proteins can become unwound (unfolded) under stressful conditions. Therefore, this proposal aims to understand how species in cold ocean and intertidal environments maintain folded proteins. The focus is on antifreeze proteins, which bind to ice and inhibit its growth, and on chemical chaperones, which are small molecules that promote proper protein folding. The blue mussel antifreeze protein will be purified and characterized. This protein and two antifreeze proteins from winter flounder will then serve as models for the study of protein folding enhancement by chemical chaperones. The antifreeze proteins will be ideal models in this work because they appear to have divergent folding limitations. The chemical chaperones of interest include those that occur naturally in the mussel and a selection of other compounds. Chaperone activity will be evaluated using standard tests for protein folding. Where appropriate, there will be more detailed structural studies on the proteins. This work will provide a novel characterized antifreeze protein from the mussel and insight into the chaperoning molecules in this species. This work will define parameters causing amyloid formation in the short winter flounder antifreeze protein and indicate the possibility of amyloid prevention by chemical chaperones. This work will also show whether the longer, highly active antifreeze protein of winter flounder forms amyloid or non-amyloid aggregates upon denaturation and it will allow us to determine whether the long antifreeze protein can be chaperoned to maintain its fold. Overall, this research will provide greater understanding of amyloid formation and chemical chaperone function. We anticipate the following specific outcomes: (1) enhanced molecular-level understanding of the species that inhabit extreme marine and intertidal environments, (2) biological strategies used by these species that could be applied artificially for the stabilization of tissues, cells or proteins in other contexts, and (3) compounds and processes that could be used to prevent or treat diseases of protein folding (such as several neurological diseases in humans).