Figure 9

Difference absorption spectra of derivatised gold sols reveal SPR peak shift following the tetra-helical peptide self-assembly. Blue solid and dashed lines show difference spectra for GNP-GST-NL derivatized gold sol reacted with GST-SNAP25 and SNAP25 respectively after subtraction of the absorption spectrum measured for the same GNP-GST-NL gold sol incubated with a non-reacting GST protein alone. Red solid and dashed lines show difference spectra for GNP-GST-SNAP25 derivatized gold sol reacted with GST-NL and NL respectively after subtraction of the absorption spectrum measured for the same GNP-GST-SNAP25 gold sol incubated with a non-reacting GST protein alone. Turquoise solid and dashed lines show absorption spectra of GNP-GST derivatized gold sol reacted with GST-SNAP25 and GST-NL respectively after subtraction of the absorption spectrum measured for the same GNP-GST gold sol incubated with GST protein alone. Dark yellow solid and dashed lines show absorption spectra of GNP-GST derivatized gold sol reacted with S25 and NL peptides respectively after subtraction of the absorption spectrum measured for the same GNP-GST gold sol incubated with GST protein alone. Schematic images of the derivatized reacted GNPs and the colour coding are the same as in Fig. 7.