Grant: Research Tools and Instruments - Category 1 (<$150,000)

This application requests funding for a high performance liquid chromatography (HPLC) system with diode array detector to separate proteins, peptides, substrates and enzyme inhibitors for study of bacteriocins and other peptides. Bacteriocins are peptide antibiotics (typically 30-60 amino acid residues in a chain) produced by bacteria for killing other species of bacteria. They are non-toxic to humans, are many orders of magnitude more powerful than conventional antibiotics (e.g. penicillin) and are effective against organisms resistant to current therapy, for example, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE). There is a great need for new antimicrobial agents such as bacteriocins. Over 50% of hospital-acquired infections are resistant to standard antibiotic therapy, and 74% of gastrointestinal infections stem from ingestion of contaminated food. The requested instrument allows isolation of minute quantities of new bacteriocins and the enzymes that produce them from complex mixtures, including cellular extracts. It also assists studies on mechanism of action of bacteriocins. Other peptides under investigation include neopetrosiamides A and B, which were isolated from a sponge near Papua New Guinea and reported by others. These peptides prevent amoebic invasion of cancer cells during metastasis. The proposed structures have been chemically synthesized by us, and as a result have been revised slightly. The new revised structures match the natural products. We propose to make new analogs with improved activity and better synthetic accessibility to allow large scale production and full pharmacological evaluation as agents to prevent spread of tumours.