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Water-Soluble Poly(γ-propargyl‑l‑glutamate) Containing Pendant Sulfonate Ions and Terminal Fluorophore: Aggregation-Enhanced Emission and Secondary Structure
journal contribution
posted on 2014-06-24, 00:00 authored by Ke-Ying Shih, Tai-Shen Hsiao, Shiang-Lin Deng, Jin-Long HongTetraphenylthiophene (TP) with aggregation-enhanced
emission (AEE)
property was used as terminal fluorophore of the water-soluble poly(γ-propargyl-l-glutamate) (PPLG)-based polymers of TP-iPPLGs to probe the
relationship between the secondary structure (α-helix) of polypeptides
and the AEE-related emission behavior. Intermolecular aggregation
of the terminal TP unit in TP-iPPLG is sterically blocked by the large
α-helical PPLG chains, leading to the weak AEE-related fluorescence
in water. In contrast, the intermolecular approach between the terminal
TP units of TP-iPPLG is accessible if TP was connected by peptide
chin in random coil structure. Therefore, the helix-to-coil transition
induced in the alkaline aqueous solution successfully enhances the
emission intensity of the TP-iPPLG solution. The pH-induced conformation
change in relationship to the AEE-related emission behavior is therefore
evaluated in this study.