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Susan Köppen
University of Bremen
22Publications
12H-index
323Citations
Publications 22
Newest
Published on Dec 10, 2018in ACS Biomaterials Science & Engineering 4.51
Nils Hildebrand3
Estimated H-index: 3
(University of Bremen),
Monika Michaelis2
Estimated H-index: 2
(University of Bremen)
+ 9 AuthorsSusan Köppen12
Estimated H-index: 12
(University of Bremen)
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...
Published on Jan 1, 2018in Physical Chemistry Chemical Physics 3.57
Nils Hildebrand3
Estimated H-index: 3
(University of Bremen),
Gang Wei36
Estimated H-index: 36
(University of Bremen)
+ 1 AuthorsLucio Colombi Ciacchi20
Estimated H-index: 20
(University of Bremen)
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...
Published on Jan 1, 2018in Physical Chemistry Chemical Physics 3.57
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...
Published on Dec 1, 2017in Computational Materials Science 2.64
Steffen Lid2
Estimated H-index: 2
(University of Bremen),
Susan Köppen12
Estimated H-index: 12
(University of Bremen),
Lucio Colombi Ciacchi20
Estimated H-index: 20
(University of Bremen)
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 ...
Published on Mar 1, 2016in Biointerphases 2.01
Ludmilla Derr4
Estimated H-index: 4
,
Nils Hildebrand3
Estimated H-index: 3
+ 5 AuthorsLucio Colombi Ciacchi20
Estimated H-index: 20
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...
Published on Apr 2, 2015in Journal of Physical Chemistry C 4.31
Nils Hildebrand3
Estimated H-index: 3
,
Susan Köppen12
Estimated H-index: 12
+ 4 AuthorsLucio Colombi Ciacchi20
Estimated H-index: 20
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...
Published on Jun 21, 2014in Journal of Chemical Physics 3.00
Svea große Holthaus2
Estimated H-index: 2
,
Susan Köppen12
Estimated H-index: 12
+ 1 AuthorsLucio Colombi Ciacchi20
Estimated H-index: 20
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...
Published on Mar 1, 2014in Journal of Cheminformatics 4.15
Walter Langel17
Estimated H-index: 17
,
Susan Köppen12
Estimated H-index: 12
(University of Bremen)
+ 2 AuthorsBastian Ohler3
Estimated H-index: 3
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...
Published on Jan 1, 2014in Physical Chemistry Chemical Physics 3.57
Adriel Domínguez1
Estimated H-index: 1
(University of Bremen),
Svea grosse Holthaus1
Estimated H-index: 1
(University of Bremen)
+ 2 AuthorsA. L. Rosa13
Estimated H-index: 13
(University of Bremen)
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...
Published on Nov 1, 2013in Surface Science 1.85
Wenke Friedrichs4
Estimated H-index: 4
(University of Greifswald),
Susan Köppen12
Estimated H-index: 12
(University of Bremen),
Walter Langel17
Estimated H-index: 17
(University of Greifswald)
Abstract Molecular dynamics simulations on two peptides TiOBP1 (RPRGFGMSRERQ) and TiOBP2 (WFCLLGCDAGCW) adsorbing on flat and rough rutile (100) TiO 2 surfaces in water are reported. Numerous contact points between charged side chains and the hydroxylated surfaces are formed with average energies of 60 and 90 kJ/mol for TiOBP1 and TiOBP2, respectively. The polar double contact points formed by adjacent positive and negative side chains immobilize the peptides on the surface more efficient than t...
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