1. Center for the Study of Hepatitis C, The Rockefeller University, 1230 York Ave., New York, New York 10021
2. Institut de Biologie et Chimie des Protéines, CNRS-UMR 5086, IFR128 BioSciences Gerland-Lyon Sud, University of Lyon, 7 Passage de Vercors, Lyon F-69367, Cedex 07, France
3. Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520