Publications de Horst Arthur Vogel

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The controlled incorporation of polypeptides and proteins into micropatterened lipid mono- and bilayers on solid supports provide important understanding of the structural organization of membrane components and have potential applications in such fields as biosensors and mol. electronics. The prepn. of the structures is done by applying either photolithog. or Langmuir-Blodgett technique, both combined with the self-assembly of sulfur-bearing lipids. Two examples of structured gold surfaces are reported adr

The thermodn. and kinetics of ligand binding to the purified serotonin 5HT3 receptor and the local environment of the bound ligand were studied by fluorescence spectroscopy using a novel fluorescein-labeled ligand GR-flu [1,2,3,9-tetrahydro-3-[(5-methyl-1H-imidazol-4-yl)methyl]-9-(3-amino-(N-fluorescein-thiocarbamoyl)-propyl)-4H-carbazol-4-one]. Electrophysiol. investigations demonstrated GR-flu to be an antagonist, and radioligand competition assays delivered a dissocn. const. of 0.32 nM. Changes in the fl

The plasma membrane is of central importance for defining the closed volume of cells in contradistinction to the extracellular environment. The plasma membrane not only serves as a boundary, but it also mediates the exchange of physical and chemical inform ...

The ability of organisms, or individual cells to sense and to react to different external and internal stimuli (light, hormones, odorants, taste) is crucial for their survival. I will report on our recent progress to investigate mol. signal recognition and transduction processes by a combination of surface sensitive phys. techiques and mol. biol. methods. Controlled self-assembly of proteins in a functionally active form on sensor surfaces is a prerequisite for investigating mol. interactions by surface-sen

A new class of lipid mols. is synthesized, based on two dipalmitoylphosphatidic mols., each extended at the lipid phosphate by a hydrophilic spacer chain of ethoxy groups of variable length, which are then coupled as a bilipid via a terminal disulfide group at the hydrophilic spacer. These anchor-bearing "thiolipids" can attach to gold substrates by forming stable gold-sulfur bonds. In this way, the authors can couple lipid bilayers to gold surfaces, with the possibility of preserving a water layer betwee

Nuclear receptors initiate transcription, interact with regulatory proteins, and are influenced by hormones, drugs, and pollutants. Herein, we discover ligand-specific mobility patterns of human estrogen receptor-a (ER) in living cells using diffusion-time ...

The expression of recombinant proteins with the Semliki Forest Virus (SFV) system has been scaled up to bioreactor scale. As a model protein for this study the human 5-HT(3) receptor was chosen. The gene for the receptor was subcloned into the SFV expression plasmid pSFV1. Virus production by in vivo packaging and production of the recombinant protein was scaled up, the latter to a reactor volume of 11.5 l. A Vibromix(TM) agitation system was chosen to overcome aggregation problems of BHK cells in suspensio

Tissue transglutaminase (tTGase) catalyzes both deamidation and transamidation of peptides and proteins by using a peptidyl glutamine as primary substrate. A precise consensus sequence for the enzyme is unknown and the ratio between deamidated and transami ...

A general method for understanding the mechanisms of ligand recognition and activation of G protein-coupled receptors has been developed. A study of ligand-receptor interactions in the prototypic seven-transmembrane neurokinin-2 receptor (NK2) using this fluorescence-based approach is presented. A fluorescent unnatural amino acid was introduced at known sites into NK2 by suppression of UAG nonsense codons with the aid of a chem. misacylated synthetic tRNA specifically designed for the incorporation of unnat

The ionotropic 5HT3 receptor was expressed in transiently transfected mammalian cells, yielding an unprecedented high concn. of up to 12 million receptors per cell. Receptor traffic in the plasma membrane of live cells was obsd. continuously over 24 h by fluorescence scanning confocal microscopy. This was possible by using 5HT3 receptor-specific fluorescent ligands with high binding affinity and low off-rate to pulse label receptors at any time after appearance on the cell surface, and label subsequently th

The function of membrane proteins is best understood if their structure in the lipid membrane is known. Here, we determined the structure of the mouse serotonin 5-HT3 receptor inserted in lipid bilayers to a resolution of 12 Å without stabilizing antibodie ...

The nicotinic acetylcholine receptor from Torpedo was immobilised in tethered membranes. Surface plasmon resonance was used to quantify the binding of ligands and antibodies to the receptor. The orientation and structural integrity of the surface-reconstituted receptor was probed using monoclonal antibodies, demonstrating that approximately 65% of the receptors present their ligand-binding site towards the lumen of the flow cell and that at least 85% of these receptors are structurally intact. The conformat

G protein-coupled receptors (GPCRs) constitute a large class of seven transmembrane proteins, which bind selectively agonists or antagonists with important consequences for cellular signaling and function. Comprehension of the mol. details of ligand binding is important for the understanding of receptor function and in turn for the design and development of novel therapeutic compds. Here we show how ligand-receptor interaction can be investigated in situ with high sensitivity on sensor surfaces by total int

How membrane receptors transduce external signals across the membrane and activate intracellular processes is a key question for fundamental research and for therapeutic purposes. Reliable in situ investigations requiest to preserve the full biological activity, the organization and the lateral mobility of proteins in the lipid membrane. Here we demonstrate the immobilization of native cell membranes on microstructured devices consisting of an array of 200 nm holes in a free standing planar SiN support. Thi

Molecular interactions of odorants with their olfactory receptors (ORs) are of central importance for the ability of the mammalian olfactory system to detect and discriminate a vast variety of odors with a limited set of receptors. How a particular OR bind ...

We report on an in vivo single-mol. study of the signaling kinetics of G protein-coupled receptors (GPCR) performed using the neurokinin 1 receptor (NK1R) as a representative member. The NK1R signaling cascade is triggered by the specific binding of a fluo ...

Conformational changes of channel activation: Five enhanced green fluorescent protein (EGFP) mols. (green cylinders) were integrated into the intracellular part of the homopentameric ionotropic 5-HT3 receptor. This allowed the detection of extracellular bi ...

In this work the authors have shown that stable gigaohm seals over micrometer-sized holes can be obtained in a time-frame of seconds by the electrophoretic self-positioning of charged lipid membranes. For the first time, single-channel events were recorded on silicon microstructures. Self-integrating channel-forming peptides, such as alamethicin are expected to have applications in screening assays based on single-channel recordings, including high-speed DNA sequencing and metabolite detection. In the futur

The 5-hydroxytryptamine receptor of type 3 was investigated by fluorescence correlation spectroscopy (FCS). Binding constants of fluorescently labeled ligands, the stoichiometry, and the mass of the receptor are readily accessible by this technique, while the duration of measurement is on the order of seconds to minutes. The receptor antagonist 1,2,3,9-tetrahydro-3-[(5-methyl-1H-imidazol-4-yl)methyl]-9-(3-aminopropyl)-4H-carbazol-4-one (GR-H) was labeled with the fluorophores rhodamine 6G, fluorescein, N-[7

Ligand-gated ion channels of the Cys loop family are receptors for small amine-contg. neurotransmitters. Charged amino acids are strongly conserved in the ligand-binding domain of these receptor proteins. To investigate the role of particular residues in ligand binding of the serotonin 5-HT3AS receptor (5-HT3R), glutamate amino acid residues at three different positions, Glu97, Glu224, and Glu235, in the extracellular N-terminal domain were substituted with aspartate and glutamine using site-directed mutage

Horst Arthur Vogel

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Biologically adressable mono- and bilayer structures by templates of sulfur-bearing molecules

Ligand binding to the serotonin 5HT3 receptor studied with a novel fluorescent ligand

Single-Vesicle Assays Using Liposomes and Cell-Derived Vesicles: From Modeling Complex Membrane Processes to Synthetic Biology and Biomedical Applications

Micro and nanoengineering of membrane receptor proteins at interfaces

A new class of thiolipids for the attachment of lipid bilayers on gold surfaces

Diffusion-Time Distribution Analysis Reveals Characteristic Ligand-Dependent Interaction Patterns of Nuclear Receptors in Living Cells

Large scale transient 5-HT3 receptor production with the Semliki Forest Virus Expression System

Deamidation and Transamidation of Substance P by Tissue Transglutaminase Revealed by Electron-Capture Dissociation Fourier Transform Mass Spectrometry (Chem. Eur. J. 2/2011)

Probing the structure and function of the tachykinin neurokinin-2 receptor through biosynthetic incorporation of fluorescent amino acids at specific sites

Monitoring expression and clustering of the ionotropic 5HT3 receptor in plasma membranes of live biological cells

The Structure of the Mouse Serotonin 5-HT3 Receptor in Lipid Vesicles

Functional immobilisation of the nicotinic acetylcholine receptor in tethered lipid membranes

Ligand Binding to G Protein-Coupled Receptors in Tethered Cell Membranes

Native membranes on subwavelentgh holes for membrane receptors analysis

The Mouse Eugenol Odorant Receptor: Structural and Functional Plasticity of a Broadly Tuned Odorant Binding Pocket

Kinetics of the initial steps of G protein-coupled receptor-mediated cellular signaling revealed by single-molecule imaging

Ligand binding transmits conformational changes across the membrane-spanning region to the intracellular side of the 5-HT3 serotonin receptor

A chip-based biosensor for the functional analysis of single ion channels

Study of ligand-receptor interactions by fluorescence correlation spectroscopy with different fluorophores: Evidence that the homopentameric 5-hydroxytryptamine type 3(As) receptor binds only one ligand

Characterization of the Ligand-binding Site of the Serotonin 5-HT3 Receptor: The Role of Glutamate Residues 97, 224,and 235