a
Department of Chemistry, University of California, Irvine, USA
E-mail: dtobias@uci.edu
b
Department of Biological Sciences, Birkbeck College, University of London, London WC1E 7HX, UK
c
Department of Physiology and Biophysics, University of California, Irvine, USA
d
Center for Biomembrane Systems, University of California, Irvine, USA