Raman spectroscopy shows antifreeze glycoproteins interact with highly oriented pyrolytic graphite

Abstract

Raman spectra of a mixture of antifreeze glycoproteins (AFGP) 6, 7 and 8 adsorbed on a highly oriented pyrolytic graphite (HOPG) surface spanning the range of 50 to 4500 cm −1 were measured. It was found that the Raman signature of AFGP had been significantly altered because of its interaction with the HOPG surface; when compared with the spectra of bulk AFGP compounds, at least three new peaks were observed around 860, 940 and 1000 cm −1 , and two other peaks that were not well resolved in the bulk spectra around 1050 and 1155 cm −1 were enhanced and well discriminated. The peak positions depended on the facet of HOPG presented to the proteins, and their relative intensities depended on the concentration of AFGP used in the adsorption experiment. The results indicated the possibility of multiple binding sites of AFGP on HOPG surfaces.

The adsorption of antifreeze glycoprotein fraction 8 on dry and wet mica

“…Recently, the interaction 0927-7765/$ -see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.colsurfb.2010.08.029 of antifreeze proteins with hydrophilic and hydrophobic surfaces, such as mica and graphite, has been explored with the hope of gaining insight into the nature of these peptide-surface interactions [29][30][31][32]. The results showed that binding to hydrophilic mica takes place over the entire surface due to its hydrophilic nature, but the adsorption of AFGPs to graphite was different.…”

Design and Synthesis of Antifreeze Glycoproteins and Mimics

“…2494 www.chembiochem.org monitor the interaction of AFGP8 on HOPG and Ag-coated glass-ceramic surfaces. [72][73] A novel attempt to mimic the active domain of AFGPs in a simple monolayer design is shown in Scheme 4. A disaccharide-functionalised alkyl thiol chain was coadsorbed with C 2 H 5 OC 2 H 4 NHCOC 15 H 30 SH to form statistically mixing self-assembled monolayers on gold.…”

Surface-enhanced Raman probing of biomolecules using Ag-coated porous glass-ceramic substrates

“…25 Two extra peaks at 938 and 1004 cm 1 were also observed from AFGP adsorbed on highly oriented pyrolytic graphite (HOPG). 26 Table 2 gives the peak positions of SERS spectrum of AFGP, compared to the corresponding peaks in the reported regular Raman spectra. 25,26 We tentatively assign the 1004 cm 1 peak to ring stretching in surface-attached AFGP molecule.…”

“…26 Table 2 gives the peak positions of SERS spectrum of AFGP, compared to the corresponding peaks in the reported regular Raman spectra. 25,26 We tentatively assign the 1004 cm 1 peak to ring stretching in surface-attached AFGP molecule. A weak 1004 cm 1 peak was also observed from glucose adsorbed on glass slide surface but not observed from either bulk glucose or bulk AFGP.…”

“…Therefore, the 1004 cm 1 peak is related to the interaction between the AFGP molecule and substrate surface. 26,27 The positions of Raman bands in the 1600 to 1700 cm 1 region in SERS spectrum showed a shift to shorter wavenumbers compared to those in regular Raman spectra. These peaks were assigned to the amide I carbonyl stretch of the polypeptide moiety of glycoprotein.…”