TY - GEN A1 - Niebuur, Bart-Jan A1 - Puchmayr, Jonas A1 - Herold, Christian A1 - Kreuzer, Lucas A1 - Hildebrand, Viet A1 - Müller-Buschbaum, Peter A1 - Laschewsky, André A1 - Papadakis, Christine M. T1 - Polysulfobetaines in aqueous solution and in thin film geometry T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Polysulfobetaines in aqueous solution show upper critical solution temperature (UCST) behavior. We investigate here the representative of this class of materials, poly (N,N-dimethyl-N-(3-methacrylamidopropyl) ammonio propane sulfonate) (PSPP), with respect to: (i) the dynamics in aqueous solution above the cloud point as function of NaBr concentration; and (ii) the swelling behavior of thin films in water vapor as function of the initial film thickness. For PSPP solutions with a concentration of 5 wt.%, the temperature dependence of the intensity autocorrelation functions is measured with dynamic light scattering as function of molar mass and NaBr concentration (0–8 mM). We found a scaling of behavior for the scattered intensity and dynamic correlation length. The resulting spinodal temperatures showed a maximum at a certain (small) NaBr concentration, which is similar to the behavior of the cloud points measured previously by turbidimetry. The critical exponent of susceptibility depends on NaBr concentration, with a minimum value where the spinodal temperature is maximum and a trend towards the mean-field value of unity with increasing NaBr concentration. In contrast, the critical exponent of the correlation length does not depend on NaBr concentration and is lower than the value of 0.5 predicted by mean-field theory. For PSPP thin films, the swelling behavior was found to depend on film thickness. A film thickness of about 100 nm turns out to be the optimum thickness needed to obtain fast hydration with H 2 O. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 713 KW - polyzwitterions KW - polysulfobetaines KW - dynamic light scattering KW - phase behavior Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427363 SN - 1866-8372 IS - 713 ER - TY - JOUR A1 - Niebuur, Bart-Jan A1 - Puchmayr, Jonas A1 - Herold, Christian A1 - Kreuzer, Lucas A1 - Hildebrand, Viet A1 - Müller-Buschbaum, Peter A1 - Laschewsky, Andre A1 - Papadakis, Christine M. T1 - Polysulfobetaines in aqueous solution and in thin film geometry JF - Materials N2 - Polysulfobetaines in aqueous solution show upper critical solution temperature (UCST) behavior. We investigate here the representative of this class of materials, poly (N,N-dimethyl-N-(3-methacrylamidopropyl) ammonio propane sulfonate) (PSPP), with respect to: (i) the dynamics in aqueous solution above the cloud point as function of NaBr concentration; and (ii) the swelling behavior of thin films in water vapor as function of the initial film thickness. For PSPP solutions with a concentration of 5 wt.%, the temperature dependence of the intensity autocorrelation functions is measured with dynamic light scattering as function of molar mass and NaBr concentration (0-8 mM). We found a scaling of behavior for the scattered intensity and dynamic correlation length. The resulting spinodal temperatures showed a maximum at a certain (small) NaBr concentration, which is similar to the behavior of the cloud points measured previously by turbidimetry. The critical exponent of susceptibility depends on NaBr concentration, with a minimum value where the spinodal temperature is maximum and a trend towards the mean-field value of unity with increasing NaBr concentration. In contrast, the critical exponent of the correlation length does not depend on NaBr concentration and is lower than the value of 0.5 predicted by mean-field theory. For PSPP thin films, the swelling behavior was found to depend on film thickness. A film thickness of about 100 nm turns out to be the optimum thickness needed to obtain fast hydration with H2O. KW - polyzwitterions KW - polysulfobetaines KW - dynamic light scattering KW - phase behavior Y1 - 2018 U6 - https://doi.org/10.3390/ma11050850 SN - 1996-1944 VL - 11 IS - 5 PB - MDPI CY - Basel ER - TY - JOUR A1 - Lilie, Hauke A1 - Baer, Dorit A1 - Kettner, Karina A1 - Weininger, Ulrich A1 - Balbach, Jochen A1 - Naumann, Manfred A1 - Mueller, Eva-Christina A1 - Otto, Albrecht A1 - Gast, Klaus A1 - Golbik, Ralph A1 - Kriegel, Thomas T1 - Yeast hexokinase isoenzyme ScHxk2 stability of a two-domain protein with discontinuous domains JF - Protein engineering design & selection N2 - The hexokinase isoenzyme 2 of Saccharomyces cerevisiae (ScHxk2) represents an archetype of a two-domain protein with the active site located in a cleft between the two domains. Binding of the substrate glucose results in a rigid body movement of the two domains leading to a cleft closure of the active site. Both domains of this enzyme are composed of discontinuous peptide sequences. This structural feature is reflected in the stability and folding of the ScHxk2 protein. Structural transitions induced by urea treatment resulted in the population of a thermodynamically stable folding intermediate, which, however, does not correspond to a molecule with one domain folded and the other unfolded. As demonstrated by different spectroscopic techniques, both domains are structurally affected by the partial denaturation. The intermediate possesses only 40% of the native secondary structural content and a substantial increase in the Stokes radius as judged by circular dichroism and dynamic light scattering analyses. One-dimensional H-1 NMR data prove that all tryptophan residues are in a non-native environment in the intermediate, indicating substantial changes in the tertiary structure. Still, the intermediate possesses quite a high stability for a transition intermediate of about Delta G = -22 kJ mol(-1). KW - dynamic light scattering KW - NMR KW - ScHxk2 KW - stability KW - transition intermediate Y1 - 2011 U6 - https://doi.org/10.1093/protein/gzq098 SN - 1741-0126 VL - 24 IS - 1-2 SP - 79 EP - 87 PB - Oxford Univ. Press CY - Oxford ER -