1. Institute of Pharmaceutical Sciences, Albert-Ludwigs-University of Freiburg, Albertstraße 25, 79104 Freiburg, Germany, Institute of Bio- and Geoscience, IBG-1: Biotechnology, Research Centre Jülich, 52425 Jülich, Germany, and Institute of Microbiology, Universität Stuttgart, Allmandring 31, 70569 Stuttgart, Germany