1. Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
2. School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
3. Biosystems R&D Department, Sandia National Laboratories, Livermore, California 94551
4. Dipartimento di Scienze Biomolecolari e Biotecnologie, Universita' degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
5. St. Vincent's Centre for Applied Medical Research, St. Vincent’s Hospital, and University of New South Wales, Sydney, New South Wales 2010, Australia