Hydrophobic Spacers Enhance the Helicity and Lectin Binding of Synthetic, pH-Responsive Glycopolypeptides

Abstract

The influence of different hydrophobic spacers on the structural and lectin binding properties of well-defined glycopolypeptides decorated with galactose moieties was investigated. All glycopolypeptides were prepared from a poly(α,l-glutamic acid) (PGA) precursor via a polymer-analogous aqueous amide coupling reaction. Thereby, two alkyl spacers of different length (C6 and C11) as well as an aromatic spacer were introduced between the backbone and the galactose moieties, as confirmed by (1)H NMR spectroscopy. The secondary structure was investigated as a function of the sugar density and the pH by circular dichroism (CD) spectroscopy. It was found that the helicity in acidic medium and thus the typical coil-to-helix transition is strongly enhanced by the hydrophobic spacers. Preliminary lectin binding tests via turbidimetric assay revealed that the spacers also significantly enhance the interaction of the glycopolypeptides with the lectin RCA120.

Synthesis and Self‐assembly of a Helical Polymer Grafted from a Foldable Polyurethane Scaffold

“…To check such possibilities, pH dependent CD spectra of PU‐PP‐1 were monitored (Figure a). At pH 10, the CD spectrum showed a maximum ellipticity at λ =218 nm and minimum ellipticity at λ =190 nm indicating random coil conformation of PU‐PP‐1 –. Whereas at pH 4.5, the polypeptide chains adopted a α‐helical conformation, as indicated by the two ellipticity minima at λ =208 and 222 nm.…”

“…The mean residue ellipticity at λ =222 nm, [ θ ] 222 , (Figure b) was used to estimate the helicity of the polypeptide chains as a function of pH –. With increase in pH, there is a strong rise of [ θ ] 222 indicating conformational switch from alpha helix to random coil.…”

“…Mean residue ellipticities were calculated using the following equation [Eq. ]: …”

Bioreducible amphiphilic block copolymers based on PCL and glycopolypeptide as multifunctional theranostic nanocarriers for drug delivery and MR imaging

“…It has been reported that lectin would specically and selectively bind to galactosyl groups. 44 In order to observe the binding interaction between lectin and the galactosyl residues more directly, we chose lectin conjugated with FITC (LEC-FITC) for the binding study. The PCL-SS-GPPs lms were prepared and treated with LEC-FITC solution and then the lms were imaged with an inverted uorescence microscope (Fig.…”

Smart Poly(imidazoyl-l-lysine): Synthesis and Reversible Helix-to-Coil Transition at Neutral pH

“…For instance, helix to coil transitions can be controlled by means of pH changes for poly( l -glutamic acid) PGA [7,8] and poly ( l -lysine) PL [9]. Recent developments in this direction include the use of polypeptide polymers to enable a structuring switch upon biologically relevant stimuli changes [1,10,11,12,13], including redox changes [14,15], metal coordination [16] or DNA binding [17].…”