Professor Frances Separovic, School of Chemistry, Bio21 Institute, The University of Melbourne.
Increased specificity of antimicrobial peptides (AMP) against bacterial lipid membranes is required for the therapeutic development of this class of membrane-active peptides. Although affinity for a particular lipid composition is often assumed to be the regulative mechanism, AMP often attack membranes mimicking the bacterial envelope almost as efficiently as those mimicking eukaryotic cells. For instance, maculatin 1.1 a 21 residue cationic AMP acts against Gram positive bacteria also has appreciable haemolytic activity. Although the secondary structure in a range of model membranes is strongly influenced by lipid composition, the peptide activity does not correlate. Dye release experiments in a competitive environment were performed to determine the AMP mechanism and affinity towards a particular membrane lipid composition. The results indicate that a distinct structure of maculatin 1.1 is not essential for lytic activity and support a pore mechanism which is regulated by the membrane lipid composition.
Professor Frances Separovic is a Biophysical Chemist who specializes in NMR spectroscopy, teaches undergraduate Chemistry, and is Head of the School of Chemistry, with her lab based at the Bio21 Institute, University of Melbourne. Frances grew up in Broken Hill, and did a BA at Macquarie and a PhD at UNSW while working full-time at CSIRO, Sydney. After 23 years at CSIRO, and a post-doc at National Institutes of Health (USA), Frances joined the University of Melbourne in 1996. Frances has developed solid-state NMR techniques to determine the structure and dynamics of membrane components in situ, specializing in peptide antibiotics and toxins within phospholipid membranes. As well as serving as General Treasurer of the Royal Australian Chemical Institute (2008-10), she was elected to Council of the Biophysical Society (USA) for 2007-10; Treasurer of Lorne Protein Conference (2006-09), Council of International Union of Pure & Applied Biophysics, IUPAB (2002-05); President of Australian Society for Biophysics, ASB (1999-2001, 2012-14); President of Australian New Zealand Society for Magnetic Resonance, ANZMAG (2011-13); and an editorial board member of Concepts in Magnetic Resonance and Accounts in Chemical Research and editor of Biochimica Biophysica Acta – Biomembranes, and European Biophysics Journal; and was Assistant Dean (EO) (2001-02) and Associate Dean (2009-10) of the Science Faculty. Frances has organized over 36 major scientific conferences and published 175 refereed papers in international journals. She was awarded the ASB Robertson Medal in 2009, the ANZMAG Medal in 2011 and was elected Fellow of the Biophysical Society (USA), ISMAR Fellow, and Fellow of the Australian Academy of Science in 2012.