Gene Center, LMU Munich, 81377 Munich and Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.|Gene Center, LMU Munich, 81377 Munich and Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany Gene Center, LMU Munich, 81377 Munich and Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.