Band positions of the CH2 asymmetrical stretching modes for (A) DPPtdIns(4,5)P2 and (B) SAPtdIns(4,5)P2 on Tris buffer as a function of surface pressure Π, with (open circles, dashed lines) and without (closed circles, solid lines) GST-PI3Kγ in the subphase. The corresponding spectra were acquired with p-polarized light at 40° angle of incidence.