The conformational populations with respect to two dihedral angles, D1 and D2, obtained by REMD (Table B) and the energy landscapes (Figure ) constructed with CV1 and CV2 afforded by MTD gave consistent distributions of conformations with respect to the glycerol moiety for all four conformationally constrained analogues as well as LysoPS(18:1) (Figure ). Comparison of the conformational distributions of the active and inactive analogues allowed us to identify the positioning of the bioactive ligand conformation (coordinates at around +60˚ (D1, CV1), -180˚ (D2, CV2)). This bioactive conformational region is among the less populated of the accessible regions of LysoPS(18:1) itself (Figure ). Notably, the measured dihedral angles of LysoPS(18:1)