Fitness landscape of intrinsically disordered proteins

ended

Mapping genotype to phenotype is a key problem of protein physics, evolutionary biology, biotechnology and medical genetics. In this project, we plan to focus on intrinsically disordered proteins, a large group of proteins whose genotype-phenotype connection is poorly understood. Such proteins do not adopt a unique native structure. Instead, they explore numerous conformations depending on external conditions. Recent bioinformatic analyses show that up to 15% of all proteins are intrinsically disordered. The critical role of intrinsically disordered proteins in cellular functions and in the onset of pathological conditions generated significant interest for their study. Much effort has been devoted to map the effects of particular mutations on protein functionality. However, no attempt to systematically study the genotype-to-phenotype link in intrinsically disordered proteins has been made. Obtaining such information is essential for sharpening theoretical models of protein folding and molecular evolution, as well as for de novo design of intrinsically disordered proteins with improved activities. The aim of this project is to experimentally measure and analyse, for the first time, the genotype-to-phenotype connection for several intrinsically disordered proteins by deep mutational scanning. We plan to focus on tardigrade proteins which are essential for their ability to survive complete desiccation. We plan to generate libraries of cells expressing hundreds of thousands of variants of these proteins and to perform competition assays to measure functionality of every variant in the library. We will then use a variety of approaches to analyse the dataset, including machine-learning algorithms to model the fitness of variants and to design new functional intrinsically disordered proteins.