FIGURE 1.

Sequestration of membrane-bound tocopherol by αTTP. A, time-dependent changes in FRET between NBD-tocopherol and fluorescent liposomes (25 μm in SET buffer) in the presence of 5 or 30 μm αTTP. Fluorescence of TRITC-DHPE was monitored at 575 nm upon excitation at 466 nm. Data collection was initiated upon mixing of the two samples in the stopped-flow device. B, dependence of the rate of tocopherol sequestration on αTTP concentrations. Rate constants were extracted from the time-dependent decrease in FRET as described under “Experimental Procedures.” Shown are averages and S.D. from >5 independent measurements at each protein concentration.