This work was supported by a European Research Council Starting Grant to H.D. (grant agreement number 256270) and the Deutsche Forschungsgemeinschaft through grants provided within the Gottfried - Wilhelm - Leibniz Program, the Excellence Clusters CIPSM (Center for Integrated Protein Science Munich), NIM (
Nanosystems Initiative Munich) and the Technische Universität München (TUM) Institute for Advanced
Study.