Figure 4
From: The lateral distance between a proton pump and ATP synthase determines the ATP-synthesis rate
Diffusion coefficients determined from measurements of lateral diffusion of co-reconstituted proteins. (A) GUVs containing two populations of cyt. bo 3, each labeled with either ATTO 647N or ATTO 594. The lipid composition was 99% DOPC or 94% DOPC and 5% DOPG (DOPC:G), and in addition 1% DPPE functionalized with a biotinyl head group. (B) Cyt. bo 3 labeled with ATTO 647N and ATP-synthase labeled with ATTO 594. (C) Left: GUVs composed of DOPC with two populations of cyt. bo 3 labeled with either Abberior STAR 635 or ATTO 594 (bo 3-bo 3). Right: GUVs composed of DOPC with cyt. bo 3 labeled with Abberior STAR 635 and ATP-synthase labeled with ATTO 594 (bo 3-ATP s.). Schemes to the right illustrate the conditions of the experiments and the conclusions (see text for details); ATTO 647N promotes the binding between cyt. bo 3 and ATP synthase in DOPC membranes but not in DOPC:G membranes, reflected in the apparent diffusion constants of cyt. bo 3 (B). The effect is not observed with only cyt. bo 3 in the membrane (A) or when ATTO 647N is replaced by the more hydrophilic Abberior STAR 635 (C). Measurements were done at pH 7.4 in 10 mM HEPES supplemented with 10 mM NaCl and 100 mM glucose. Error bars represent standard deviation from measurements with five samples.
