CHED 348 |
| A biosensor selectively detects the presence of a biological entity and signals its presence. For this purpose, we used the host molecule cucurbit[8]uril (Q8), which binds simultaneously to two aromatic guests with high affinity in aqueous solution. We recently discovered that if the guest molecule methyl viologen (MV) is used, then a tryptophan-containing peptide is selected as the second guest. The optical properties of Q8-MV in complex with a series of tryptophan derivatives and peptides were studied by UV-visible and fluorescence spectroscopy with the goals of quantifying the formation of each complex and characterizing the mechanism of binding. Upon binding to Q8-MV, a charge-transfer absorbance at 420-440 nm (å = 300-600 M-1cm-1) and the quenching of indole fluorescence were observed for each ternary complex. We find that the relationship between the quenching of indole fluorescence and the fraction of guest bound to Q8-MV is linear across the series at a given concentration. The quantitative, optical output of peptide binding provides proof-of-principle for a new biosensor and is promising for the development of a high-throughput optical binding assay for the recognition of amino acids and peptides. |
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Undergraduate Research Poster Session: Organic Chemistry
11:00 AM-1:00 PM, Monday, 27 March 2006 Georgia World Congress Center -- Ex. Hall B4, Poster
Division of Chemical Education |