1. From the Cardiovascular Division (R.S.H., F.C., T.J.H., J.C.K., M.G., M.A.) and Randall Division of Cell and Molecular Biophysics (M.G.), King’s College London, London, UK; and the Department of Physical Biochemistry (G.F.), Max-Planck Institute of Molecular Physiology, Dortmund, Germany.