(65ah) Mimicking of Iron-Sulfur Cluster Proteins: Synthesis of Half-Amphiphilic Dendrimer

Iron sulfur proteins are used in the body for electron transport, control of gene expression, substrate binding, and enzyme activity. The behavior of the iron-sulfur cluster depends greatly on the protein structure surrounding it. In particular, the redox potential of the cluster and the rate of electron transfer to and from the cluster can vary over a wide range depending on the protein environment in which the cluster is found. To understand how structure affects these parameters, an artificial but controlled set of structures are being synthesized and studied. These structures are dendrimers of varying hydrophobicity with the iron sulfur cluster at their topological center. The dendrimers encapsulate the iron sulfur cluster and allow us to explore the electronic properties of the cluster while eliminating the solvent environment of the body. The half hydrophilic/half hydrophobic dendrimer is being explored for its encapsulating properties. The half hydrophobic is predicted to act like a lipid and wrap around the cluster to protect it. The half hydrophilic is predicted to act allow the dendrimer to be dissolved in polar solvents, like water. This structure is predicted to allow the dendrimer to have a dual role of core protection and water solubility. Dendrimers are being prepared with one, two and three generations (layers of hyperbranching) through a series of organic synthesis steps. Subsequently, electrochemistry measurements are being performed to determine their redox potentials and rates of electron transfer.