FIGURE 1.

Preparation and characterization of PECAM-1-containing nanodiscs. A, PECAM-1 was affinity-purified from human platelets, while recombinant MSP was purified from bacterial lysates. B, after self-assembly in the presence of phosphatidylcholine, PECAM-1-containing nanodiscs were separated from empty nanodiscs by gel-filtration chromatography and their Stokes diameters calculated by their elution relative to a series of known molecular mass standards using y = −0.7043× + 21.351. C, SDS-PAGE analysis of faster eluting Peak A shows the presence of ∼16 nm particles containing both PECAM-1 and MSP, as well slower-eluting Peak B comprised of ∼9 nm particles containing only the MSP protein. D and E, representative negative stained electron micrographs of empty (D) and PECAM-1-containing (E) nanodiscs. Note the single, centrally-placed electron dense entity present in the PECAM-1, but not the empty, nanodiscs.