1. Department of Chemistry, University of Cape Town, Private Bag, Rondebosch 7701, South Africa
2. Institute for Infectious Diseases and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
3. Division of Pharmacology, Department of Medicine, University of Cape Town, Observatory 7925, South Africa
4. Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia