Water-soluble, stable helical polypeptide-grafted cyclodextrin bioconjugates: synthesis, secondary and self-assembly structures, and inclusion complex with guest compounds

Abstract

In this study, we synthesized a linear copolymer, poly(g-propargyl-L-glutamate-graft-cyclodextrin) (PPLG-g-CD), through Huisgen [2 + 3] cycloadditions (click reactions) of monoazido-functionalized bcyclodextrin (N 3 -CD) with the propargyl side chains, obtaining a self-assembling structure with a highly stable a-helical conformation and water-solubility. We used Fourier transform infrared spectroscopy, solid state nuclear magnetic resonance spectroscopy, wide-angle X-ray diffraction, and circular dichroism analyses in the solid state and in solution to characterize the transformations of the secondary structures between a-helix and b-sheet conformations. Temperature-dependent FTIR spectroscopic analyses revealed that the presence of the CD units on the PPLG side chain increased the stability of the a-helix conformation toward elevated temperatures, relative to that of pure PPLG. In addition, the presence of the CD cavities allowed the grafted polymers to form inclusion complexes with low-molecular-weight compounds, providing macromolecules with potential biomedical applications.

Self-Assembling Hydrogels Based on a Complementary Host–Guest Peptide Amphiphile Pair

“…This structure is suitable for association with hydrophobic guest motifs of appropriate size and polarity such as adamantane (Ada) derivatives. 29,[32][33][34] A number of CD-Ada peptide-based systems have proven functional as soft materials, 35 delivery devices, 36,37 and chemo- 38 and bio-sensors. 39 However, to our knowledge, both the benefits and functionalities of this host-guest pair have not yet been translated into PA self-assembled hydrogels.…”

Strong emission of 2,4,6-triphenylpyridine-functionalized polytyrosine and hydrogen-bonding interactions with poly(4-vinylpyridine)

“…19 In addition to the addition of functional moieties into the main chain or a side chain of polypeptides, the polymers is another convenient method for improving the thermal or self-assembly behavior of polypeptides. [16][17][18] For example, we solution. The chain behavior of PTyr/P4VP was turned to interpolymer complex aggregates and separated random coil based on FTIR spectroscopy and wide-angle X-ray diffraction analyses.…”

Self-assembled structures from PEGylated polypeptide block copolymers synthesized using a combination of ATRP, ROP, and click chemistry

“…The b-sheet structure was characterized by a negative minimum band near 218 nm and the random coil structure was characterized by a small positive band at 218 nm and a large negative band near 200 nm. 51,52 The solutions of both of the PS-b-(PPLG-g-MEO 2 ) copolymers in MeOH displayed negative bands at 208 and 222 nm, corresponding to an a-helical structure for each of these two diblock copolymers. Furthermore, the widths of the amide I signals of the PS-b-(PPLG-g-MEO 2 ) (W 1/2 ¼ 38 cm À1 ) copolymers were much narrower than those of the PS-b-PPLG (W 1/2 ¼ 53 cm À1 ) copolymers, indicating more order in the hexagonal cylinder packing of the a-helical secondary structure for the PS-b-(PPLGg-MEO 2 ) copolymers.…”

“…Monoazidefunctionalized MEO 2 , g-propargyl-L-glutamate, and PS-b-PPLG were prepared according to previous literature procedures. [47][48][49][50][51]…”