1. Department of Molecular Biology & Genetics, University of Aarhus, Gustav Wieds Vej 10 C, DK-8000 Aarhus C, Denmark
2. Department of Physics, West Chester University, West Chester, PA 19383, USA
3. Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
4. Pennsylvania Muscle Institute, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA