With the support of the Organic Dynamics Program in the Chemistry Division, Professor Maria Ngu-Schwemlein, of the Chemistry Department at the University of South Alabama, will focus on the development of chemosensing cyclopeptides that bind selective toxic heavy metal ions and signal specific metal ion binding. The scientific objectives of this project are to (i) develop a clearer understanding of the interaction of acidic cyclooctapeptides with heavy metal ions (Pb2+, Hg2+ and Cd2+) by a structure and binding activity relationship study of a series of fluorophore-tagged acidic cyclooctapeptides, (ii) understand how the bound metal ion modulates the fluorescence emission properties of these fluorogenic cyclopeptides, (iii) identify the origins of the binding specificity between the donor atoms on the cyclooctapeptide and the heavy metal ions through solid state (X-ray diffraction), and solution state (NMR) studies, and (iv) to utilize these discoveries to develop new cyclopeptide-derived fluorophore-spacer-receptor systems that will allow one to completely dictate selective toxic metal ion binding with a specific fluorescence signal. The fluorophore-tagged cyclopeptides will be prepared by solid phase peptide syntheses. Their metal-ion binding and associated thermodynamic parameters will be evaluated by isothermal titration calorimetry. Specific metal ion signaling by the fluorogenic cyclopeptides will be studied by fluorescence spectroscopy. Ground state properties of some cyclopeptide and metal ion complexes will also be investigated by NMR spectroscopy and X-ray diffraction.
With the support of the Organic Dynamics Program in the Chemistry Division, Professor Ngu-Schwemlein will perform research that could lead to optical sensors for the detection of heavy metal ions. These would have wide applications in environmental chemistry and be directly relevant to the development of a more accurate and rapid identification of harmful metal ions in the environment. The PI will continue her successful training of undergraduate students, taking advantage of the scientifically rich, multi-disciplinary environment at the University of South Alabama and nearby universities. The above proposed multidisciplinary research study will have direct impact on both the departmental research environment and its objective to prepare undergraduates for entry into advanced degree programs and careers in science.
