Susan Köppen
University of Bremen
Publications 23
#1Martin Kulke (University of Greifswald)H-Index: 1
Last.Susan KöppenH-Index: 12
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As a key player in cell adhesion the glycoprotein fibronectin is involved in the complex mechanobiology of the extracellular matrix. Although the function of many modules in the fibronectin molecule has already been understood the structure and biological relevance of the C-terminal cross-linked region (CTXL) still remains unclear. It is known that fibronectin is only phosphorylated in the CTXL domain, but no results have been presented to date, which indicate a biological function based on this...
#1Nils Hildebrand (University of Bremen)H-Index: 4
#2Monika Michaelis (University of Bremen)H-Index: 2
Last.Lucio Colombi Ciacchi (University of Bremen)H-Index: 22
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Adsorption of enzymes on solid surfaces may lead to conformational changes that reduce their catalytic conversion activity and are thus detrimental to the efficiency of biotechnology or biosensing applications. This work is a joint theoretical and experimental endeavor in which we identify and quantify the conformational changes that chymotrypsin undergoes when in contact with the surface of amorphous silica nanoparticles. For this purpose, we use circular dichroism spectroscopy, standard molecu...
1 CitationsSource
#1Nils Hildebrand (University of Bremen)H-Index: 4
#2Gang Wei (University of Bremen)H-Index: 38
Last.Lucio Colombi Ciacchi (University of Bremen)H-Index: 22
view all 4 authors...
The force spectra of proteins detaching from oxide surfaces measured by atomic force microscopy (AFM) often present complex patterns of peaks, which are difficult to correlate with individual bond-breaking events at the atomic scale. In this work we rationalize experimental AFM force spectra of hen-egg-white lysozyme detaching from silica by means of all-atom steered molecular dynamics (SMD) simulations. In particular, we demonstrate that the native tertiary structure of lysozyme is preserved if...
4 CitationsSource
#1Ina BuchholzH-Index: 1
#2Peter NestlerH-Index: 1
Last.Mihaela DelceaH-Index: 20
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One of the major problems in the study of the dynamics of proteins is the visualization of changing conformations that are important for processes ranging from enzyme catalysis to signaling. A protein exhibiting conformational dynamics is the soluble blood protein beta 2-glycoprotein I (beta2GPI), which exists in two conformations: the closed (circular) form and the open (linear) form. It is hypothesized that an increased proportion of the open conformation leads to the autoimmune disease antiph...
2 CitationsSource
#1Steffen Lid (University of Bremen)H-Index: 2
#2Susan Köppen (University of Bremen)H-Index: 12
Last.Lucio Colombi Ciacchi (University of Bremen)H-Index: 22
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Abstract We present realistic models of amorphous alumina/water interfaces taking into account the chemical termination with hydroxyl groups and chemisorbed water molecules, as predicted by DFT-based MD simulations. On the basis of these models we parametrize a fixed-charges force field to describe the interactions within alumina and across the alumina/water interface, which can be seamlessly combined with biomolecular force fields via straightforward combination rules. The potential parameters ...
2 CitationsSource
#1Ludmilla DerrH-Index: 4
#2Nils HildebrandH-Index: 4
Last.Lucio Colombi CiacchiH-Index: 22
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In order to understand fundamental interactions at the interface between immobilized enzymes and ceramic supports, the authors compare the adsorption features of chymotrypsin on SiO2 and TiO2 colloidal particles by means of a combination of adsorption experiments and molecular dynamics simulations. While the dependency of the adsorption amount on pH is consistent with the trend predicted the Derjaguin-Landau-Verwey-Overbeek theory, other effects can only be rationalized if the atomic-scale detai...
9 CitationsSource
The adsorption of α-chymotrypsin and hen egg white lysozyme on amorphous silica is studied by molecular dynamics (MD) simulations in comparison with adsorption experiments. Protein–surface interaction profiles are computed in implicit solvent at the level of DLVO theory. These reveal a preferential adsorption orientation for chymotrypsin, driven by its large dipole moment, with its α-helical regions pointing toward the surface. Instead, a less clear orientational preference characterizes lysozym...
26 CitationsSource
We investigate the adsorption behavior of four different amino acids (glutamine, glutamate, serine, cysteine) on the zinc oxide (101¯0) surface, comparing the geometry and energy associated with a number of different adsorption configurations. In doing this, we highlight the benefits and limits of using density-functional tight-binding (DFTB) with respect to standard density functional theory (DFT). The DFTB method is found to reliably reproduce the DFT adsorption geometries. Analysis of the ads...
3 CitationsSource
#1Walter LangelH-Index: 17
#2Susan Köppen (University of Bremen)H-Index: 12
Last.Bastian OhlerH-Index: 4
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The interface between titanium dioxide and biological solution is relevant for the bioactivity of titanium implants. Adhesion phenomena between inorganic solids are of general interest for mineralization and bone formation processes. Such interfaces are complex systems with many constituents including the hydroxylated metal oxide support, hydrocarbon contamination, ionic water solution and a variety of biopolymers. Our computational methods comprise classical molecular dynamics with around 106 a...
7 CitationsSource
#1Adriel Domínguez (University of Bremen)H-Index: 1
#2Svea grosse Holthaus (University of Bremen)H-Index: 1
Last.A. L. Rosa (University of Bremen)H-Index: 14
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Density functional theory (DFT) and Car–Parinello molecular dynamic simulations were employed to investigate the interaction of acetic acid with non-polar facets of ultra-thin ZnO nanowires. We consider both a dry and a water environment as well as different molecule coverages for the hydrated system. Our calculations reveal that the fully-covered nanowire is energetically favored in the aqueous environment at room temperature. We also identified a minor influence of liquid water on the denticit...
6 CitationsSource