1. CNRS UMR5153, Muséum National d’Histoire Naturelle USM0503, and INSERM U565, 43 rue Cuvier, 75231 Paris cedex 05, France, UPMC, Paris 75005, France, DISMA, Università di Milano, via Celoria 2, 20133 Milano, Italy, INSERM U-837, COL, IRCL, Place Verdun, 59045 Lille, France, and Sigma-tau Industrie Farmaceutiche Riunite SpA, Pomezia, Italy