Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), 69118 Heidelberg, Center for Molecular Biology Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany and Interdisciplinary Center for Scientific Computing (IWR), 69120 Heidelberg, Germany Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies (HITS), 69118 Heidelberg, Center for Molecular Biology Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany and Interdisciplinary Center for Scientific Computing (IWR), 69120 Heidelberg, Germany.