Preparation of LPS monolayers was conducted as described by us previously.
Briefly, LPS monolayers were produced by depositing a RaLPS suspension in 60% CH 3 Cl, 39% MeOH, and 1% H 2 O (v/v) onto a cleaned air/liquid interface of 20 mM HEPES pH 7.2 buffer solution containing with 5 mM CaCl 2 or 3 mM EDTA. The resulting film was then compressed to a series of surface pressures, at which XRR and GIXD analysis of the monolayer took place.