1. Protein Structure-Function Research Unit, School of Molecular and Cell Biology , University of the Witwatersrand , Johannesburg , Gauteng , South Africa
2. Molecular Sciences Institute, School of Chemistry , University of the Witwatersrand , Johannesburg , Gauteng , South Africa
3. Department of Chemistry , University of South Africa, Unisa Science Campus , 28 Pioneer Avenue , Florida, Roodepoort , Gauteng , South Africa