@article{AndraeMerkelDurmazetal.2014, author = {Andrae, Karsten and Merkel, Stefan and Durmaz, Vedat and Fackeldey, Konstantin and K{\"o}ppen, Robert and Weber, Marcus and Koch, Matthias}, title = {Investigation of the Ergopeptide Epimerization Process}, volume = {2}, journal = {Computation}, number = {3}, doi = {10.3390/computation2030102}, pages = {102 -- 111}, year = {2014}, abstract = {Ergopeptides, like ergocornine and a-ergocryptine, exist in an S- and in an R-configuration. Kinetic experiments imply that certain configurations are preferred depending on the solvent. The experimental methods are explained in this article. Furthermore, computational methods are used to understand this configurational preference. Standard quantum chemical methods can predict the favored configurations by using minimum energy calculations on the potential energy landscape. However, the explicit role of the solvent is not revealed by this type of methods. In order to better understand its influence, classical mechanical molecular simulations are applied. It appears from our research that "folding" the ergopeptide molecules into an intermediate state (between the S- and the R-configuration) is mechanically hindered for the preferred configurations.}, language = {en} } @article{AndraeDurmazFackeldeyetal.2013, author = {Andrae, Karsten and Durmaz, Vedat and Fackeldey, Konstantin and Scharkoi, Olga and Weber, Marcus}, title = {Medizin aus dem Computer}, volume = {62}, journal = {Der Anaesthesist}, number = {7}, publisher = {Springer}, doi = {10.1007/s00101-013-2202-x}, pages = {561 -- 557}, year = {2013}, language = {de} } @article{DurmazSchmidtSabrietal.2013, author = {Durmaz, Vedat and Schmidt, Sebastian and Sabri, Peggy and Piechotta, Christian and Weber, Marcus}, title = {A hands-off linear interaction energy approach to binding mode and affinity estimation of estrogens}, volume = {53}, journal = {Journal of Chemical Information and Modeling}, number = {10}, pages = {2681 -- 2688}, year = {2013}, language = {en} } @article{Durmaz2015, author = {Durmaz, Vedat}, title = {Markov model-based polymer assembly from force field-parameterized building blocks}, volume = {29}, journal = {Journal of Computer-Aided Molecular Design}, doi = {10.1007/s10822-014-9817-0}, pages = {225 -- 232}, year = {2015}, abstract = {A conventional by hand construction and parameterization of a polymer model for the purpose of molecular simulations can quickly become very workintensive and time-consuming. Using the example of polyglycerol, I present a polymer decompostion strategy yielding a set of five monomeric residues that are convenient for an instantaneous assembly and subsequent force field simulation of a polyglycerol polymer model. Force field parameters have been developed in accordance with the classical Amber force field. Partial charges of each unit were fitted to the electrostatic potential using quantumchemical methods and slightly modified in order to guarantee a neutral total polymer charge. In contrast to similarly constructed models of amino acid and nucleotide sequences, the glycerol building blocks may yield an arbitrary degree of bifurcations depending on the underlying probabilistic model. The iterative development of the overall structure as well as the relation of linear to branching units is controlled by a simple Markov model which is presented with few algorithmic details. The resulting polymer is highly suitable for classical explicit water molecular dynamics simulations on the atomistic level after a structural relaxation step. Moreover, the decomposition strategy presented here can easily be adopted to many other (co)polymers.}, language = {en} } @article{HeyeBeckerLuetkeEverslohetal.2016, author = {Heye, Katharina and Becker, Dennis and L{\"u}tke-Eversloh, Christian and Durmaz, Vedat and Ternes, Thomas and Oetken, Matthias and Oehlmann, J{\"o}rg}, title = {Effects of carbamazepine and two of its metabolites on the non-biting midge Chironomus riparius in a sediment full life cycle toxicity test}, volume = {98}, journal = {Water Research}, pages = {19 -- 27}, year = {2016}, abstract = {The antiepileptic drug carbamazepine (CBZ) and its main metabolites carbamazepine-10,11-epoxide (EP-CBZ) and 10,11-dihydro-10,11-dihydroxy-carbamazepine (DiOH-CBZ) were chosen as test substances to assess chronic toxicity on the non-biting midge Chironomus riparius. All three substances were tested in a 40-day sediment full life cycle test (according to OECD 233) in which mortality, emergence, fertility, and clutch size were evaluated. In addition, these parameters were integrated into the population growth rate to reveal population relevant effects. With an LC50 of 0.203 mg/kg (time-weighted mean), the metabolite EP-CBZ was significantly more toxic than the parent substance CBZ (LC50: 1.11 mg/kg). Especially mortality, emergence, and fertility showed to be sensitive parameters under the exposure to CBZ and EP-CBZ. By using classical molecular dynamics (MD) simulations, the binding of CBZ to the ecdysone receptor was investigated as one possible mode of action but showed to be unlikely. The second metabolite DiOH-CBZ did not show any effects within the tested concentration rage (0.171 - 1.22 mg/kg). Even though CBZ was less toxic compared to EP-CBZ, CBZ is found in the environment at much higher concentrations and causes therefore a higher potential risk for sediment dwelling organisms compared to its metabolites. Nevertheless, the current study illustrates the importance of including commonly found metabolites into the risk assessment of parent substances.}, language = {en} }