Figure 6
Interactions between cd1NiR and liposomes, cNOR-liposomes and native membranes. (a) Fluorescence autocorrelation curves measured on a sample containing 5 nM cd1NiR-STAR 635 (red), and after addition of LUVs containing 2.5 nM cNOR (green). The dashed (black) line is a fit of the data using a model with two diffusion times. As references, measurements of a sample containing free dye STAR 635 (red dotted line) and a sample with LUVs containing cNOR labelled with ATTO 594 are also shown. (b) Titration of 5 nM cd1NiR-STAR 635 with increasing concentrations of LUVs containing unlabeled cNOR in buffer containing 2 mM KCl (black) or 100 mM KCl (green), and titration with the same amount of LUVs without protein (white). The plot shows the amplitude of the slow component where Fmax has been set to 1. The data for LUVs with and without protein were fitted with a simple binding model (see text for details). (c) FCS curves from titration experiments with native membranes from P. denitrificans grown under aerobic (green) or anaerobic denitrifying (red) conditions. Sonicated membranes were added to a solution of 50 nM cd1NiR-STAR 635 (black dotted line). A sample with DOPC-liposomes produced in the same way containing cNOR labelled with ATTO 594 is shown as reference (black line).
