FIGURE 3.

Extent of subunit exchange by Superose 6 analysis. (A) ¹⁴C-αA R116C homocomplexes were incubated for 15 h at 37 °C in PBS with nonradioactive WTαA homocomplexes in a 1:1 molar ratio to allow exchange to occur. The samples were loaded onto a Superose 6 size-exclusion column for analysis. Fractions were collected and measured for absorbance at 280 nm (●) and counts per minute (○). (B) αA R116C was incubated for 15 h at 37 °C in PBS in the absence of WTαA. The elution profile using absorbance at 280 nm (■) is overlaid with the radioactivity profile (○) from panel A to demonstrate the effect of WTαA subunits on the elution of αA R116C (shaded area). (C) A₂₈₀ profiles of WTαA (□) and αA R116C (■) after separate incubations for 15 h at 37 °C in PBS.