1. Department of Biology, Technion‐Israel Institute of Technology Haifa 32000 Israel
2. Institut fur Mikrobiologie und Molekularbiologie, Justus‐Liebig‐Universitat Giessen Heinrich‐Buff‐Ring 26 35392 Giessen Germany
3. EMBL Heidelberg Meyerhofstrasse 1 69117 Heidelberg Germany