Conversion of different forms of β2GPI. Electron microscopy visualization of β2GPI treated at high and low pH. (A) Purified plasma β2GPI. (B) Plasma β2GPI after dialysis for 2 days at pH 11.5 with subsequent neutralization to pH 7.4. (C) Plasma β2GPI, first dialyzed against pH 11.5, then dialyzed for 2 days against pH 3.5 and subsequently neutralized to pH 7.4. (D-F) Representation of panels A through C, respectively. (G) SDS-PAA gel electrophoresis of purified plasma β2GPI (lane 1), β2GPI after dialysis against pH 11.5 (lane 2) and β2GPI first dialyzed against pH 11.5 followed by dialysis against pH 3.5 (lane 3). All 3 samples show a single band at approximately 43 kDa. (H) The percentages of circular and open conformation in purified plasma β2GPI (A), opened β2GPI (B), and reclosed β2GPI (C).
