Electron-Transfer Across Artificial Beta-Sheets

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9307791 Ogawa Professor Ogawa of Bowling Green State University will investigate electron transfer across artificial beta-pleated sheets with support from the Inorganic, Bioinorganic, and Organometallic Chemistry Program. He will synthesize compounds based on oligopeptides; these will be joined in pairs at the ends so as to induce the beta-pleated sheet conformation. Electron transfer donor and acceptor sites will be attached to these capped oligopeptides so that the role of beta pleated sheets in mediating electron transfer can be assessed. The molecules will be characterized by circular dichroism and multinuclear nmr spectroscopy, and where possible by x-ray diffraction. Electron transfer will be initiated by flash photolysis and monitored by fluorescence and absorption spectroscopy. The primary goal will be to determine if beta-pleated sheets are unusually effective in mediating electron transfer, as has been predicted theoretically. %%% The transfer of an electron through proteins is an essential component of many life processes. Often this must occur through distances that are long on the atomic scale. It has been suggested that certain structural motifs within proteins are especially effective in fostering such long range electron transfer events. In particular, structures known as "beta-pleated sheets" have been implicated. Experiments to test this hypothesis will be conducted by designing and synthesizing artificial beta-pleated sheets; these molecules will be constructed with sites that are able to participate in electron transfer reactions. The rates of electron transfer will then be measured and compared with those of similar molecules that lack the beta-pleated sheets. The information to be obtained will refine our understanding of the ways that proteins perform their functions. ***