Intramolecular Transfer of Excitation Energy,Complexation with Metal Ions,and Interactions with Liposomes of Cyclo [tryptophyl-sarcosyl-sarcosyl-Nϵ-dansyllysyl-prolyl] |
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Authors: | Shunsaku Kimura Yukio Imanishi |
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Abstract: | A cyclic pentapeptide containing an energy donor group and an energy acceptor group within the molecule, cyclo Trp-Sar-Sar-Lys (DNS)-Pro], was synthesized. Its conformation, complexation with metal ions, intramolecular energy transfer, and interaction with liposomes were investigated. The precursor, cyclo Trp-Sar-Sar Lys ( Z )-Pro], contained one cis-sarcosyl peptide bond and a β-turn in which the Pro-residue occupied the 3rd position. This cyclic pentapeptide formed a complex selectively with Ba2+ and its binding constant in 95% aqueous methanol solution was 2.0 × 103 1 · mol?1. The intramolecular energy-transfer efficiency of cyclo Trp-Sar-Sar-Lys (DNS)-Pro] was almost constant between ? 60° and 40° in ethanol, while it increased at temperatures lower than 34° in liposomes as a result of the pre-transition of the lipid assembly. On the other hand, the intramolecular energy transfer efficiency of cyclo Trp-Sar-Sar-Lys (DNS)-Pro] decreased upon complexation with Ba2+. |
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