1. The University of Queensland, School of Biomedical Sciences, Brisbane, QLD, 4072, Australia
2. Molecular Targets Program, Centre for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, MD, 21702, USA
3. Chemical Biology Laboratory, Centre for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, MD, 21702, USA
4. Natural Products Branch, Centre for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, MD, 21702, USA
5. Peptide Therapeutics, Genentech Inc, 1 DNA Way, South San Francisco, CA, 94080, USA