Self-assembled tethered bimolecular lipid membranes. 2009

Eva-Kathrin Sinner, and Sandra Ritz, and Renate Naumann, and Stefan Schiller, and Wolfgang Knoll
Max Planck Institute for Polymer Research, Mainz, Germany.

This chapter describes some of the strategies developed in our group for designing, constructing and structurally and functionally characterizing tethered bimolecular lipid membranes (tBLM). We introduce this platform as a novel model membrane system that complements the existing ones, for example, Langmuir monolayers, vesicular liposomal dispersions and bimolecular ("black") lipid membranes. Moreover, it offers the additional advantage of allowing for studies of the influence of membrane structure and order on the function of integral proteins, for example, on how the composition and organization of lipids in a mixed membrane influence the ion translocation activity of integral channel proteins. The first strategy that we introduce concerns the preparation of tethered monolayers by the self-assembly of telechelics. Their molecular architecture with a headgroup, a spacer unit (the "tether") and the amphiphile that mimics the lipid molecule allows them to bind specifically to the solid support thus forming the proximal layer of the final architecture. After fusion of vesicles that could contain reconstituted proteins from a liposomal dispersion in contact to this monolayer the tethered bimolecular lipid membrane is obtained. This can then be characterized by a broad range of surface analytical techniques, including surface plasmon spectroscopies, the quartz crystal microbalance, fluorescence and IR spectroscopies, and electrochemical techniques, to mention a few. It is shown that this concept allows for the construction of tethered lipid bilayers with outstanding electrical properties including resistivities in excess of 10 MOmega cm2. A modified strategy uses the assembly of peptides as spacers that couple covalently via their engineered sulfhydryl or lipoic acid groups at the N-terminus to the employed gold substrate, while their C-terminus is being activated afterward for the coupling of, for example, dimyristoylphosphatidylethanol amine (DMPE) lipid molecules via the NH2 moiety of their headgroups. It is demonstrated that these membranes are well suited for the in situ synthesis of membrane protein by a cell-free expression approach. The vectorial integration of an in vitro synthesized odorant receptor, OR5 from the rat, is demonstrated by means of antibodies that specifically bind to a tag at the N-terminus of the receptor and is read out by surface plasmon fluorescence spectroscopy. A completely different strategy employs his-tagged membrane proteins in their solubilized form binding to a surface-attached Ni(+)-NTA monolayer generating a well-oriented protein layer the density of which can be easily controlled by online monitoring the binding (assembly) step by surface plasmon spectroscopy. Moreover, the attachment of the his-tag to either the C- or the N-terminus allows for the complete control of the protein orientation. After the exchange of the detergent micelle by a lipid bilayer via a surface dialysis procedure an electrically very well isolating protein-tethered membrane is formed. We show that this "wiring" of the functional units allows for the (external) manipulation of the oxidation state of the redox-protein cytochrome c Oxidase by the control of the potential applied to the gold substrate which is used as the working electrode in an electrochemical attachment.

UI MeSH Term Description Entries
D008051 Lipid Bilayers Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes. Bilayers, Lipid,Bilayer, Lipid,Lipid Bilayer
D008055 Lipids A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed) Lipid
D011506 Proteins Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein. Gene Products, Protein,Gene Proteins,Protein,Protein Gene Products,Proteins, Gene
D004563 Electrochemistry The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes. Electrochemistries
D013050 Spectrometry, Fluorescence Measurement of the intensity and quality of fluorescence. Fluorescence Spectrophotometry,Fluorescence Spectroscopy,Spectrofluorometry,Fluorescence Spectrometry,Spectrophotometry, Fluorescence,Spectroscopy, Fluorescence
D013055 Spectrophotometry, Infrared Spectrophotometry in the infrared region, usually for the purpose of chemical analysis through measurement of absorption spectra associated with rotational and vibrational energy levels of molecules. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed) IR Spectra,Infrared Spectrophotometry,IR Spectras,Spectra, IR
D020349 Surface Plasmon Resonance A biosensing technique in which biomolecules capable of binding to specific analytes or ligands are first immobilized on one side of a metallic film. Light is then focused on the opposite side of the film to excite the surface plasmons, that is, the oscillations of free electrons propagating along the film's surface. The refractive index of light reflecting off this surface is measured. When the immobilized biomolecules are bound by their ligands, an alteration in surface plasmons on the opposite side of the film is created which is directly proportional to the change in bound, or adsorbed, mass. Binding is measured by changes in the refractive index. The technique is used to study biomolecular interactions, such as antigen-antibody binding. Plasmon Resonance, Surface,Plasmon Resonances, Surface,Resonance, Surface Plasmon,Resonances, Surface Plasmon,Surface Plasmon Resonances

Related Publications

Eva-Kathrin Sinner, and Sandra Ritz, and Renate Naumann, and Stefan Schiller, and Wolfgang Knoll
June 2004, Bioelectrochemistry (Amsterdam, Netherlands),
Eva-Kathrin Sinner, and Sandra Ritz, and Renate Naumann, and Stefan Schiller, and Wolfgang Knoll
September 1976, Biophysical journal,
Eva-Kathrin Sinner, and Sandra Ritz, and Renate Naumann, and Stefan Schiller, and Wolfgang Knoll
January 1978, Biofizika,
Eva-Kathrin Sinner, and Sandra Ritz, and Renate Naumann, and Stefan Schiller, and Wolfgang Knoll
April 1970, Biochimica et biophysica acta,
Eva-Kathrin Sinner, and Sandra Ritz, and Renate Naumann, and Stefan Schiller, and Wolfgang Knoll
September 1989, Physical review letters,
Eva-Kathrin Sinner, and Sandra Ritz, and Renate Naumann, and Stefan Schiller, and Wolfgang Knoll
December 2020, Membranes,
Eva-Kathrin Sinner, and Sandra Ritz, and Renate Naumann, and Stefan Schiller, and Wolfgang Knoll
May 1970, Science (New York, N.Y.),
Eva-Kathrin Sinner, and Sandra Ritz, and Renate Naumann, and Stefan Schiller, and Wolfgang Knoll
December 1984, Indian journal of biochemistry & biophysics,
Eva-Kathrin Sinner, and Sandra Ritz, and Renate Naumann, and Stefan Schiller, and Wolfgang Knoll
January 1974, Methods in enzymology,
Eva-Kathrin Sinner, and Sandra Ritz, and Renate Naumann, and Stefan Schiller, and Wolfgang Knoll
March 1970, Biochimica et biophysica acta,
Copied contents to your clipboard!