Biomimetic Models to Investigate Membrane Biophysics Affecting Lipid–Protein Interaction

Abstract

Biological membranes are highly dynamic in their ability to orchestrate vital mechanisms including cellular protection, organelle compartmentalization, cellular biomechanics, nutrient transport, molecular/enzymatic recognition, and membrane fusion. Controlling lipid composition of different membranes allows cells to regulate their membrane characteristics, thus modifying their physical properties to permit specific protein interactions and drive structural function (membrane deformation facilitates vesicle budding and fusion) and signal transduction. Yet, how lipids control protein structure and function is still poorly understood and needs systematic investigation. In this review, we explore different in vitro membrane models and summarize our current understanding of the interplay between membrane biophysical properties and lipid-protein interaction, taken as example few proteins involved in muscular activity (dystrophin), digestion and Legionella pneumophila effector protein DrrA. The monolayer model with its movable barriers aims to mimic any membrane deformation while surface pressure modulation imitates lipid packing and membrane curvature changes. It is frequently used to investigate peripheral protein binding to the lipid headgroups. Examples of how lipid lateral pressure modifies protein interaction and organization within the membrane are presented using various biophysical techniques. Interestingly, the shear elasticity and surface viscosity of the monolayer will increase upon specific protein(s) binding, supporting the importance of such mechanical link for membrane stability. The lipid bilayer models such as vesicles are not only used to investigate direct protein binding based on the lipid nature, but more importantly to assess how local membrane curvature (vesicles with different size) influence the binding properties of a protein. Also, supported lipid bilayer model has been used widely to characterize diffusion law of lipids within the bilayer and/or protein/biomolecule binding and diffusion on the membrane. These membrane models continue to elucidate important advances regarding the dynamic properties harmonizing lipid-protein interaction.

Simple Does Not Mean Trivial: Behavior of Phosphatidic Acid in Lipid Mono- and Bilayers

“…This can result in changes for instance in membrane curvature, mechanical bending, compressibility, thickness, lateral diffusion, and/or local water permeability. Changes in lipid composition may also contribute to the formation of membrane defects and changes in lipid headgroup conformation and/or presentation at the membrane interface, all of which were reported, along with membrane curvature, to modulate protein recruitment [11][12][13][14]. The local concentration of PA may significantly exceed the average concentration due to transient activation of a number of PA-producing enzymes [1].…”

Rationally designed foldameric adjuvants enhance antibiotic efficacy via promoting membrane hyperpolarization

“…For this purpose, the circular dichroism (CD) spectrum of each molecule was recorded in the presence and absence of large unilamellar vesicles (LUVs) containing 1,2-dioleoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-phosphoglycerol (DOPC/DOPG), which are regularly employed as a model for biological membranes. 43 All sequences displayed a random coil curve in the absence of LUVs (Fig. S4a †).…”

Lipid Nanosystems and Serum Protein as Biomimetic Interfaces: Predicting the Biodistribution of a Caffeic Acid-Based Antioxidant

“…As LUVs' preparation methods are easy and reproducible they are widely used as biomimetic systems to study the biophysical interactions between bioactives and membranes. 19,33,37,41,42 Besides lipid vesicles, micelles were also used as mimetic models of the biliary salt micelles and were prepared by aqueous dispersion of NaDC at a concentration above the critical micellar concentration (6 mM). 43 In order to obtain labelled membrane nanosystems, ethanolic stock solutions of fluorescent probes were added to a chloroform solution of lipids in a lipid: probe molar ratio always greater than 100:1, to prevent structural changes of the membrane model system.…”