What is the fine-grained topic of the following text: R. Linser, M. Dasari, U. Fink, P. Schmieder, J.-M. Lopez del Amo, S. Marcovic, M. Hiller, H. Oschkinat, D. Oesterheld, B. Reif, “Proton detected solid state NMR of fibrillar and membrane proteins”, Angew. Only return the topic.
Proton detected solid state NMR of fibrillar and membrane proteins