Recklinghausen, Germany
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Hanel K.,Jülich Research Center | Mockel L.,Jülich Research Center | Brummel M.,Westfalische Hochschule | Peiris K.,Westfalische Hochschule | And 5 more authors.
Protein Expression and Purification | Year: 2014

Viral accessory proteins of the human immunodeficiency virus (HIV), including virus protein R (Vpr), are crucial for the efficient replication of the virus in the host organism. While functional data are available for HIV-1 Vpr, there is a paucity of data describing the function and structure of HIV-2 Vpr. In this report, the construction of a His6-MBP-intein1-Vpr- intein2-Cyt b5-His6 fusion protein is presented. Unlike previous research efforts where only microgram quantities of HIV-1 Vpr could be produced, this construct enabled soluble milligram yields via an Escherichia coli over-expression system. Straightforward protein purification of HIV-2 Vpr was achieved by standard chromatography routines and autocatalytic intein cleavage. Preliminary structural studies by circular dichroism (CD) and NMR spectroscopy revealed that the protein is stable in the presence of micellar concentrations of the detergent DPC and adopts an α-helix secondary structure. © 2013 Elsevier Inc. All rights reserved.


Silber D.,Karlsruhe Institute of Technology | Kowalski P.M.,Jülich Research Center | Traeger F.,Westfalische Hochschule | Buchholz M.,Karlsruhe Institute of Technology | And 3 more authors.
Nature Communications | Year: 2016

Under ambient conditions, almost all metals are coated by an oxide. These coatings, the result of a chemical reaction, are not passive. Many of them bind, activate and modify adsorbed molecules, processes that are exploited, for example, in heterogeneous catalysis and photochemistry. Here we report an effect of general importance that governs the bonding, structure formation and dissociation of molecules on oxidic substrates. For a specific example, methanol adsorbed on the rutile TiO2 (110) single crystal surface, we demonstrate by using a combination of experimental and theoretical techniques that strongly bonding adsorbates can lift surface relaxations beyond their adsorption site, which leads to a significant substrate-mediated interaction between adsorbates. The result is a complex superstructure consisting of pairs of methanol molecules and unoccupied adsorption sites. Infrared spectroscopy reveals that the paired methanol molecules remain intact and do not deprotonate on the defect-free terraces of the rutile TiO2 (110) surface. © The Author(s) 2016.


PubMed | Jülich Research Center, Westfalische Hochschule and Heinrich Heine University Düsseldorf
Type: | Journal: Protein expression and purification | Year: 2014

Viral accessory proteins of the human immunodeficiency virus (HIV), including virus protein R (Vpr), are crucial for the efficient replication of the virus in the host organism. While functional data are available for HIV-1 Vpr, there is a paucity of data describing the function and structure of HIV-2 Vpr. In this report, the construction of a His6-MBP-intein1-Vpr-intein2-Cyt b5-His6 fusion protein is presented. Unlike previous research efforts where only microgram quantities of HIV-1 Vpr could be produced, this construct enabled soluble milligram yields via an Escherichia coli over-expression system. Straightforward protein purification of HIV-2 Vpr was achieved by standard chromatography routines and autocatalytic intein cleavage. Preliminary structural studies by circular dichroism (CD) and NMR spectroscopy revealed that the protein is stable in the presence of micellar concentrations of the detergent DPC and adopts an -helix secondary structure.


PubMed | Karlsruhe Institute of Technology, The Interdisciplinary Center, Jülich Research Center and Westfalische Hochschule
Type: | Journal: Nature communications | Year: 2016

Under ambient conditions, almost all metals are coated by an oxide. These coatings, the result of a chemical reaction, are not passive. Many of them bind, activate and modify adsorbed molecules, processes that are exploited, for example, in heterogeneous catalysis and photochemistry. Here we report an effect of general importance that governs the bonding, structure formation and dissociation of molecules on oxidic substrates. For a specific example, methanol adsorbed on the rutile TiO


Osterloh N.,Ruhr University Bochum | Silber D.,Ruhr University Bochum | Traeger F.,Westfalische Hochschule | Woll C.,Karlsruhe Institute of Technology
Physica Status Solidi (B) Basic Research | Year: 2013

The adsorption of water on r-TiO2(110) has been investigated with thermal desorption spectroscopy (TDS) and helium atom scattering. Conventional TDS using a mass spectrometer and He-TDS monitoring reflected He beam intensity consistently show the existence of a structurally well-defined monolayer as well as a highly ordered second layer of water and a disordered multilayer phase. He diffraction patterns recorded along the high symmetry [001], $[1{\bar {1}}0]$, and $[1{\bar {1}}1]$ directions reveal a well-ordered superstructure with (1×1) symmetry, providing strong evidence for the absence of a partially dissociated monolayer on the perfect parts of the substrate. No changes in the diffraction patterns are observed after irradiation with UV-light. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Esposito A.,Free University of Bozen Bolzano | Kirschberg M.,Westfalische Hochschule
FEMS Microbiology Letters | Year: 2014

The word 'metagenomic' is one of the most used words in environmental microbiology especially in recent years, yet sometimes it is a little overused. Can studies targeting a single gene be considered 'metagenomic'? It is more controversial than once thought, maybe a possible solution may come from an etymological analysis of the word. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.


Zughart W.,Bundesamt fur Naturschutz | Beismann H.,Westfalische Hochschule | Schroder W.,University of Vechta
BioRisk | Year: 2013

The deliberate release of genetically modified organisms (GMOs) implies the potential occurrence of environmental impacts which are either unexpected or only partially predictable and, thus, necessitates development of appropriate monitoring methodology. Therefore, new challenges have to be met when implementing the post market environmental monitoring (PMEM) of genetically modified organisms (GMOs), which is mandatory according to the European legal framework. According to Directive 2001/18/EC PMEM has to follow standard methodologies, wherever available and appropriate. To provide all involved parties with appropriate standard monitoring methods, the so called VDI Guidelines are developed by working groups established by the Association of German Engineers (VDI). These working groups are composed by external experts participating on a voluntary basis. The VDI is an independent technical standardisation body. All Guidelines are published in German and English and can therefore be used throughout Europe. VDI Guidelines are available in the field of exposure of the environment to GM plants (e.g. standardised sampling of pollen, standardised observation of hybrids or ferals), biomolecular analyses (e.g. standardised extraction and detection of transgenes or their products in different environmental compartments), and the standardised monitoring of effects on non-target organisms (e.g. butterflies, wild bees, amphibians or soil organisms). The aim beyond this work is to facilitate generation of reliable and comparable monitoring data and enable an effective and efficient PMEM with high acceptability to the scientific community as well as the general public. © Wiebke Züghart et al.


PubMed | Westfalische Hochschule and University of Hamburg
Type: Journal Article | Journal: Physical review. E | Year: 2016

We show that strong non-Markovian effects can be revealed by the steady-state two-dimensional (2D) photon echo spectra at asymptotic waiting times. For this, we use a simple dimer toy model that is strongly coupled to a harmonic bath with parameters typical for photoactive biomolecules. We calculate the 2D photon echo spectra employing both the numerically exact hierarchy equation of motion and the quasiadiabatic path integral approach and compare these results with approximate results from a time-nonlocal quantum master equation approach. While the latter correctly reproduces the exact population dynamics at long times, it fails at the same time to correctly describe the 2D photon echo spectra at long waiting times. The differences show that non-Markovian effects are much more important for the steady-state 2D photon echoes than for the equilibrium populations. Thus, accurate theoretical descriptions of the energy transfer dynamics in biomolecular complexes have to be based on numerically exact simulations of the environmental fluctuations when nonlinear response functions are analyzed.

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