1. Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL 60612, USA.
2. Department of Cell Ultrastructure and Molecular Biology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
3. Chemistry Department, University of Virginia, Charlottesville, VA 22901, USA.
4. Departments of Chemistry and Pathology, University of Virginia, Charlottesville, VA 22901, USA.