1. Institute for Chemical and Environmental Research (IIQAB)-CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain, Department of Physiology, Faculty of Pharmacy, University of Barcelona, Avgda. Joan XXIII s/n, 08028 Barcelona, Spain, Servei de Ressonància Magnètica Nuclear, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain, and Institute of Microbiology, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany