Figure 1
From: A biomimetic design for a sialylated, glycan-specific smart polymer
Binding affinity evaluation of L-aspartate-L-phenylalanine dimethyl ester (abbreviated DF) complexed with five core monosaccharides. (a) Partial hydrogen nuclear magnetic resonance (1H NMR) spectra from the titration of DF (60 mM) with different molar ratios (0~10) of Neu5Ac in deuterated dimethylsulfoxide (d6-DMSO) at 25 °C. (b–d) Relationship between the chemical shift of the amide-a proton and the molar ratios of the monosaccharide (guest) to DF obtained from the hydrogen nuclear magnetic resonance (1H NMR) titration experiment. Guests: Neu5Ac (b), Gal (c) and GlcNAc (d). The red lines are nonlinear fitting curves, which were used to calculate the association constants (Ka). (e) Comparison of Ka for DF interacted with Neu5Ac, Gal, GlcNAc, Man or Glc, illustrating the satisfactory chemoselectivity of the DF receptor for different monosaccharides. (f) Possible binding mode of DF with Neu5Ac obtained from quantum chemistry calculations (Gaussian, density function theory (DFT) at the 6-311G level, solvent: water); hydrogen bonds with different lengths are indicated by the green dashed lines, which are well consistent with the chemical shift changes in the 1H NMR spectra (b).
