Fig. 3: Subunit stoichiometry of δΔN-α fused FoF1.
From: Engineering of ATP synthase for enhancement of proton-to-ATP ratio
a SDS-PAGE analysis of the purified wild-type (WT) Bacillus PS3 FoF1 and the δΔN-α fused FoF1. Each sample was derived from a single purification batch. 3 μg of FoF1 was loaded in each lane. The molecular masses of the δΔN-α, α, β, γ, a, δ, b, εΔC, and c-subunits are 63, 55, 53, 32, 26, 20, 19, 9, and 7 kDa, respectively. The experiment was independently repeated three times with similar results. b The band intensity vs total protein amount. A single series of diluted FoF1 from the same purification batch was loaded into a gel and subjected to SDS-PAGE analysis. The band intensity of each subunit was plotted against the total amount of FoF1 loaded for SDS-PAGE analysis. The plots were fitted with a linear function. The slopes for γ (black), a- (red), and b-subunits (blue) were determined to be 2082, 502, and 2004 (arb. units/µg) for the WT FoF1, and 1521, 821, and 2675 (arb. units/µg) for the δΔN-α fused FoF1, respectively. By normalizing the slopes of the a- and b-subunits to the slope of the γ subunit of each FoF1, the stoichiometries of the a- and b-subunits of the δΔN-α fused FoF1 were estimated to be 2.2 ( = (821/1521)/(502/2082)) and 1.8 ( = (2675/1521)/(2004/2082)) times higher than those of the wild-type FoF1, respectively.
