Binding of Small Oligopeptides

Following this concept, we set out to find efficient receptors for tetrapeptidic substrates. As a first target the hydrophobic tetrapeptide, Ac-Val-Val-Ile-Ala-OH was chosen. This tetrapeptide represents the C-terminal sequence of the amyloid-/ - 

One must, of course ensure that the fluorescence activity observed in the assay is really due to a selective complexation of the tetrapeptide substrate by the receptor. This was done by appropriate control experiments  

Because the labeled tetrapeptide does not bind to the unmodified solid support Amino-TentaGel, the observed fluorescence activity is not because of unspecific interaction with the solid support itself. 

The dansylated spacer alone does not bind to the receptor library, showing that the binding indeed occurs between the peptide part of the substrate and the receptor. 

The percentage of receptors that bind the substrate is concentration-dependent - at high concentrations nearly all of the library members bind the substrate, which shows that the observed binding specificity is not a result of selective quenching of the dansyl fluorescence rather than selective binding. 

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