Fig. 5

Characterization of molecular interactions mediating association and alignment of GQ11 nanofibers. GQ11 and NQ11 nanofibers adopted similar secondary structures under dilute conditions when analyzed with a Fourier-transform infrared spectroscopy and b circular dichroism. c In the gel state, GQ11 had a peak at 1668 cm⁻¹ attributed to the GlcNAc C=O group that was absent in NQ11 gels, whereas peaks at 1620 cm⁻¹ related to the peptide backbone were unchanged. d GQ11 nanofibers demonstrated a strong increase in ellipticity at 203 nm as a function of Ficoll concentration, whereas e NQ11 ellipticity at 203 nm remained unchanged in the presence of Ficoll. When compared to GQ11 nanofibers alone (f), GQ11 nanofibers also demonstrated an increase in ellipticity at 203 nm in the presence of soluble GlcNAc (g). In contrast, when compared to NQ11 alone (h), ellipticity of NQ11 was unchanged in the presence of soluble GlcNAc (i). In g and i, “Obs.” denotes the observed spectrum for a sample of nanofiber+GlcNAc, whereas “Exp.” denotes the expected spectrum based on the sum of the nanofiber and GlcNAc spectra shown under “Individual”. Note that in both f and h, the same representative spectrum is used for the GlcNAc sample