High sensitivity NMR for structure determination of neurodegenerative disease associated protein aggregates in native contexts

For an organism to survive, its proteins must adopt a diversity of conformations in a challenging environment where macromolecular crowding can derail even robust biological pathways. This situation becomes critical when considering proteins with energetic folding landscapes that permit many conformational states. In these cases, the environment can clearly influence the conformation by favoring one pathway over another. Because the aggregating proteins that are responsible for neurodegenerative diseases like Alzheimer’s and Parkinson’s diseases often have identical sequences in healthy and diseased individuals, differences in cellular environment are responsible for the conformational switch. Yet, despite the importance of the environment for protein folding, structural investigations of biomolecules are typically confined to in vitro systems, which cannot capture important structural features imposed by biological environments. Solid-state NMR spectroscopy is currently undergoing a “sensitivity renaissance” with the development of dynamic nuclear polarization (DNP). Experiments that would require decades of experimental time with traditional ssNMR methods can be collected in a day with DNP NMR. Moreover, while most structural biology approaches require purified samples, NMR spectroscopy does not. Because NMR reports quantitatively on the relative populations - with atomic level precision - it can report on the identity and relative abundance of structural polymorphs. Here, we will capitalize on the methodology for in cell structural biology using DNP- assisted NMR we have developed in our group to determine if and how biological settings influence the conformations of both the highly ordered and intrinsically disordered regions with atomic level precision.