The Protein-Tethered Lipid Bilayer: A Novel Mimic of the Biological Membrane

Abstract

A new concept of solid-supported tethered bilayer lipid membrane (tBLM) for the functional incorporation of membrane proteins is introduced. The incorporated protein itself acts as the tethering molecule resulting in a versatile system in which the protein determines the characteristics of the submembraneous space. This architecture is achieved through a metal chelating surface, to which histidine-tagged (His-tagged) membrane proteins are able to bind in a reversible manner. The tethered bilayer lipid membrane is generated by substitution of protein-bound detergent molecules with lipids using in-situ dialysis or adsorption. The system is characterized by surface plasmon resonance, quartz crystal microbalance, and electrochemical impedance spectroscopy. His-tagged cytochrome c oxidase (CcO) is used as a model protein in this study. However, the new system should be applicable to all recombinant membrane proteins bearing a terminal His-tag. In particular, combination of surface immobilization and membrane reconstitution opens new prospects for the investigation of functional membrane proteins by various surface-sensitive techniques under a defined electric field.

Controlled solvent-exchange deposition of phospholipid membranes onto solid surfaces

“…For instance, the Langmuir-Blodgett deposition allows the deposition of asymmetric bilayers, 22 dip-pen technology facilitates the fabrication of biomolecular arrays, 8 spin coating enables the quick generation of highly oriented, homogeneous bilayer stacks with defined thickness, 20 and evaporation induced self-assembly permits the creation of patterned nanocomposites of dissimilar materials. 21 In some applications, exposure of the sample to air should be avoided, and solution-based deposition of supported bilayers is preferred; 22 such procedures would also be suitable for a wider class of surfaces, including hydrophobic surfaces 23 or, in principle, also solid particles such as silica or glass beads. 24,25 Tiberg et al, 26 for example, reported a simple method of this kind for preparing model lipid bilayers by coadsorption with a nonionic surfactant.…”

Two-Dimensional Correlation Analysis of Sum-Frequency Vibrational Spectra of Langmuir Monolayers

“…Langmuir monolayers, which are monomolecular films of amphiphilic organic molecules at an air/water interface, have been investigated very extensively as a planar model system having a rich phase-transition behavior, and also as a simple system mimicking biological membranes [1][2][3][4]. Among the important issues concerning Langmuir monolayer are the conformation of molecules in the monolayer and its phase-transition behavior, and many experimental techniques such as X-ray diffraction/reflectivity [5,6], Brewster angle microscopy [7,8], ellipsometry [6,[8][9][10][11], and infrared reflection-absorption spectroscopy [9] have been employed to address these issues in the Langmuir monolayer system.…”

One-step direct reconstitution of biomembranes onto cationic organic polymer bead supports

“…One of the advanced systems for studying the structures and functions of 3 biomembranes involves the incorporation of integral and/or peripheral membrane proteins into an artificial phospholipid-based SLM in the non-denatured state, thus maintaining their asymmetric native orientation [14]. Controlling the orientation and density of the proteins in the membranes still seems to be one of the major setbacks of this approach.…”