1. Department of Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands.,
2. Department of Biochemistry and Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.,
3. Laboratoire J. Maetz, Département de Biologie Cellulaire et Moléculaire du Commissariat à l'Energie Atomique, 06230 Villefranche‐sur‐mer, France.