Publications de Horst Arthur Vogel

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The question how G-protein-coupled receptors transduce an extracellular signal by a sequence of transmembrane conformational transitions into an intracellular response remains to be solved at molecular detail. Herein, we use molecular dynamics simulations ...

The reversible, oriented immobilization of proteins on solid surfaces is a prerequisite for the investigation of mol. interactions and the controlled formation of supramol. assemblies. This paper describes a generally applicable method using a synthetic chelator thioalkane that can be self-assembled on gold surfaces. The reversible binding of an anti-lysozyme Fab fragment modified with a C-terminal hexahistidine extension was monitored and the apparent dissocn. consts. detd. using surface plasmon resonance.

The binding of the fluorescein-labeled antagonist GR-flu ([1,2,3,9-tetrahydro-3-[(5-methyl-1H-imidazol-4-yl)methyl]-9-(3-amino- (N-fluoresceinthiocarbamoyl)propyl)-4H-carbazol-4-one]) to a purified, detergent-solubilized ligand-gated ion channel, the type-3 serotonin (5-hydroxytryptamine, 5HT) receptor (5HT3R), was characterized by frequency-domain time-resolved fluorescence spectroscopy (TRFS). Detailed understanding of how ligands interact with the homopentameric receptor was obtained. While a 1:1 stoichi

Small-angle neutron scattering data for lipid bilayers in excess water are presented. The method of solvent contrast variation was applied. The variation of scattering intensity with the scattering angle could be analyzed in terms of the model of scattering by quasi-2-dimensional systems of O. Kratky and G. Porod (1948). From this, the bilayer thickness of unilamellar vesicles of dimyristoyllecithin was detd. to be 41 .ANG. at 310 K. Several typical mixts. of different lecithins with varying chain lengths a

Chem. and biol. labeling is fundamental for the elucidation of the function of proteins within biochem. cellular networks. In particular, fluorescent probes allow detection of mol. interactions, mobility and conformational changes of proteins in live cells with high temporal and spatial resoln. We present a generic method to label proteins in vivo selectively, rapidly (seconds) and reversibly, with small mol. probes that can have a wide variety of properties. These probes comprise a chromophore and a metal-

The basic photosynthetic unit contg. the reaction center and the light-harvesting I complex (RC-LHI) of the purple non-sulfur bacterium Rhodospirillum rubrum was purified and reconstituted into two-dimensional (2D) membrane crystals. Transmission electron microscopy using conventional techniques and cryoelectron microscopy of the purified single particles and of 2D crystals yielded a projection of the RC-LHI complex at a resoln. of at least 1.6 nm. In this projection the LHI ring appears to have a square sy

The effects of a variety of inhibitors suggested that the promastigote surface protease (PSP) of Leishmania might be a Zn metalloprotease. To investigate this possibility, at. emission and absorption spectroscopic analyses were conducted which showed that PSP contains 1 atom of Zn per 63-kilodalton (kDa) monomer. Further studies showed that the enzyme could be biosynthetically labeled with 65ZnCl2. The comparison of the amino acid sequence of L. major PSP with 9 other Zn metalloproteases revealed significan

A fluorescently labeled ligand for the 5-HT3 serotonin receptor was synthesized and its sub-nanomolar affinity for the purified, detergent solubilized receptor was measured. The change in the ligand's fluorescence upon receptor binding was used to directly measure its dissocn. const. for receptor binding, to det. the pharmacol. of the receptor, and finally to characterize the binding site of the receptor. A total internal reflection fluorescence (TIRF) assay for the 5-HT3 receptor was developed, which is su

A method for determining the presence of a molecule coupled to the cytoplasmic side of a cellular membrane is disclosed. The method is implemented in a microfluidic setting and is particularly suitable for determining the presence and/or the activity of a ...

We report on a generic method to detect and iden- tify the molecular profile of exosomes either derived from cultured cell lines or isolated from biofluids. Exosomes are nanovesicles shed by cells into their microenvironment and carry the molecular identit ...

The screening of ligands for membrane receptor proteins is central to the discovery of new pharmaceutical drugs. We present a general method to reversibly attach receptor proteins via an affinity tag to a quartz surface and subsequently detect with high sensitivity the real-time binding of ligands by total internal reflection fluorescence. A serotonin-gated ion channel protein was immobilized, and the binding of a fluorescent ligand was investigated. The affinity and the kinetic parameters of binding were m

High-aspect-ratio, monocryst. Cd chloride nanowires doped with fluorescent CdS nanoparticles were synthesized using planar lipid membranes as templates. Cd2+ ions bound to the lipid bilayers (a) are released at low pH to the nanometer-sized, interlamellar ...

Hydrophobins self assemble into amphipathic films at hydrophobic-hydrophilic interfaces. These proteins are involved in a broad range of processes in fungal development. We have studied the conformational changes that accompany the self-assembly of the hydrophobin SC3 with polarization-modulation IR reflection absorption spectroscopy, attenuated total reflection Fourier transform IR spectroscopy, and CD, and related them to changes in morphol. as obsd. by electron microscopy. Three states of SC3 have been s

Imaging samples on a surface by mass spectrometry (MS) requires the combination of MS detection with a scanning mode that enables localized desorption and ionization and/or detection of sample analytes with good spatial resolution. We have developed a new ...

During the membrane insertion process the major coat protein of bacteriophage M13 assumes a conformation in which two transmembrane helixes corresponding to the leader sequence and the anchor region in the mature part of the protein coming into close contact with each other. Previous studies on the mol. mechanism of membrane insertion of M13 procoat protein have shown that this interaction between the two helixes might drive the actual translocation process. We investigated the intramol. distance between th

Fluorescence anisotropy measurements on isotropically distributed membranes yield the well-known orientational order parameter as a measure of orientational fluctuations of the fluorophore that are fast compared to the fluorescence lifetime. Measurements on oriented membranes provide 4 order parameters, 2 for fast orientational fluctuations and 2 for slow, from which their approx. angular distributions can be derived. This is exemplified for the fluctuations of lipids in membranes with and without protein.

A simple method has been developed for the prodn. of Au surfaces which are uniformly flat over large areas. Si wafers serve as substrates for the evapn. of thin Au layers. A glass slide glued onto the Au film allows successful sepn. of the Au layer from the Si oxide surface. The process leaves a flat Au surface suitable for chem. modification. The surfaces were characterized using scanning force microscopy. An av. roughness of 2.5 .ANG. over areas up to 1000 mm2 was found. Scanning force microscopy images o

Monolayers of gramicidin A, pure and in mixts. with dimyristoylphosphatidylcholine (DMPC), were studied in situ at the air/H2O and air/D2O interfaces by polarization-modulated IR reflection absorption spectroscopy (PM-IRRAS). Simulations of the entire set of amide I absorption modes were also performed, using complete parameter sets for different conformations based on published normal mode calcns. The structure of gramicidin A in the DMPC monolayer could clearly be assigned to a b6.3 helix. Quant. anal. of

Lateral diffusion enables efficient interactions between membrane proteins leading to signal transmission across the plasma membrane. An open question is how the spatio-temporal distribution of cell surface receptors influences the transmembrane signaling ...

Systems for positioning and/or analyzing samples such as cells, vesicles, cellular organelles, and fragments, derivs., and mixts. thereof, for elec. and/or optical anal., esp. relating to the presence and/or activity of ion channels. [on SciFinder (R)]

Horst Arthur Vogel

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W246(6.48) Opens a Gate for a Continuous Intrinsic Water Pathway during Activation of the Adenosine A(2A) Receptor

Immobilization of histidine-tagged proteins on gold surfaces using chelator thioalkanes

In vitro and in vivo ligand binding to the 5HT3 serotonin receptor characterised by time-resolved fluorescence spectroscopy

Small-angle neutron scattering of aqueous dispersions of lipids and lipid mixtures. A contrast variation study

Reversible site-selective labeling of membrane proteins in live cells

Are the light-harvesting I complexes from Rhodospirillum rubrum arranged around the reaction center in a square geometry?

Characterization of the promastigote surface protease of Leishmania as a membrane-bound zinc endopeptidase

Fluorescence techniques for fundamental and applied studies of membrane protein receptors: the 5-HT3 serotonin receptor

Method and system for determining intracellular mediators' activity

Molecular screening of cancer-derived exosomes by surface plasmon resonance spectroscopy

Screening Ligands for Membrane Protein Receptors by Total Internal Reflectance Fluorescence: The 5-HT3 Serotonin Receptor

Synthesis of nanoscopic optical fibers using lipid membranes as templates

Self-assembly of the hydrophobin SC3 proceeds via two structural intermediates

Electrostatic Spray Ionization Mass Spectrometry Imaging

Fluorescence Resonance Energy Transfer Shows a Close Helix-Helix Distance in the Transmembrane M13 Procoat Protein

Fast and slow orientational fluctuations in membranes

Uniformly Flat Gold Surfaces: Imaging the Domain Structure of Organic Monolayers Using Scanning Force Microscopy

Polarization-modulated FTIR spectroscopy of lipid/gramicidin monolayers at the air/water interface

Single-Molecule Imaging Deciphers the Relation between Mobility and Signaling of a Prototypical G Protein-Coupled Receptor in Living Cells

Multiaperture sample positioning and analysis system