Langmuir-monolayer methodologies for characterizing protein-lipid interactions.

The Langmuir-monolayer technique is a convenient method that allows for continuous control over several membrane-specific parameters, such as molecular packing, physical states, lateral pressure and lipid composition. Lipid monolayers are well suited for applications involving the Langmuir-monolayer technique: they are very well-defined, stable, homogeneous and two-dimensional, and they have planar geometry. In this review, some features of monolayer methodologies based on the Langmuir-monolayer technique are described, with a focus on the step-wise procedures that can be applied to characterize protein-lipid interactions at the lipid monolayer/buffer interface in order to maximize the information concerning the mechanism of interaction between the protein and the lipid monolayer.