1. Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Street 32, 117984 Moscow, Russia, Faculte de Pharmacie, URA CNRS 1924, Bd Jean Moulin 27, 13385 Marseille Cedex 5, France, and Laboratoire de Chimie Bacterienne, UPR 7221, CNRS, Chemin J. Aiguier 31, 13009 Marseille, France