Figure 4

The presence of the nucleotides GTP and GDP does not affect the IM30-mediated change of the DOPG lipid order. (a) Laurdan fluorescence emission spectra of 0.1 mM DOPG liposomes were recorded in absence and presence of 2.5 mM GTP or GDP and 1 µM SynIM30 WT. Solid lines show the spectra in absence of IM30. Dashed lines show the spectra in the presence of SynIM30 WT. Binding of IM30 leads to a clear shift of the Laurdan fluorescence maximum. (b) The GP value was calculated for DOPG liposomes in the presence and absence of GTP and GDP without addition of SynIM30. Addition of the nucleotides leads to a small, but still significant decrease of the GP-value. SD, n = 6 two-sample Student´s t-test, *p < 0.05, **p < 0.01, ***p < 0.005. (c) The ΔGP after addition of SynIM30 WT to DOPG liposomes is not significantly changed in the presence of the nucleotides GTP or GDP, respectively. (SD, n = 6 two-sample Student´s t-test).