Gene Center, Ludwig-Maximilians-Universitxc3xa4t Mxc3xbcnchen, Munich 81377, Germany, Computational Biology, Max Planck Institute for Biophysical Chemistry, Gxc3xb6ttingen 37077, Germany and TUM, Department of Informatics, Bioinformatics & Computational Biology-I12, Garching 85748, Germany.