CHED 274 |
| Cyclopeptide-based motifs are promising structural scaffolds for selective metal ion binding and sensing. Previously we showed that cyclo[D-Leu-Leu-D-Leu-Trp-(D-Glu-Glu)2] exhibited selective binding and specific fluorescent responses towards some divalent metal ions. Here, we examined the interactions between fluorophore tagged, heterochiral cyclooctapeptides, containing the Cys2/His2 or Met2/His2 sequences, and some toxic heavy metal ions. The binding affinities of P1-3 for Hg2+, Pb2+, and Cd2+ were studied by isothermal titration calorimetry. Specific signaling by the Dansyl or Trp tagged cyclopeptides was assessed by fluorescence spectroscopy. The results indicate that P1-3 exhibit significant metal ion binding for Hg2+ (K > 106 M-1) and weaker interactions with Pb2+ and Cd2+. Fluorescence responses in the presence of these metal ions correlate with relative metal ion binding affinities. The above study shows that cyclooctapeptides containing residues found in the zinc finger binding motifs could be useful for the design of Hg2+ sensors. |
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Undergraduate Research Poster Session: Analytical Chemistry
11:00 AM-1:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Poster
Division of Chemical Education |