Interactions of IDPs with Membranes Using Dark-State Exchange NMR Spectroscopy.

Membrane interactions of proteins play a role in essential cellular processes in both physiological and disease states. The structural flexibility of intrinsically disordered proteins (IDPs) allows for interactions with multiple partners, including membranes. However, determining conformational states of IDPs when interacting with membranes can be challenging. Here we describe the use of nuclear magnetic resonance (NMR), including dark-state exchange saturation transfer (DEST), to probe IDP-membrane interactions in order to determine whether there is an interaction, which residues participate, and the extent/nature of the interaction between the protein and the membrane. Using α-synuclein and tau as typical examples, we provide protocols for how the membrane interactions of IDPs can be probed, including details of how the samples should be prepared and guidelines on how to interpret the results.