1. Laboratoire d’Ingénierie des Systèmes Macromoléculaires, UPR 9027, Aix Marseille Université, 31 Chemin Joseph Aiguier, 13402 Marseilles, France, Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, U.K., and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854-8082