TY  - GEN
A1  - Walkowiak, Jacek
A1  - Lu, Yan
A1  - Gradzielski, Michael
A1  - Zauscher, Stefan
A1  - Ballauff, Matthias
T1  - Thermodynamic analysis of the uptake of a protein in a spherical polyelectrolyte brush
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - A thermodynamic study of the adsorption of Human Serum Albumin (HSA) onto spherical polyelectrolyte brushes (SPBs) by isothermal titration calorimetry (ITC) is presented. The SPBs are composed of a solid polystyrene core bearing long chains of poly(acrylic acid). ITC measurements done at different temperatures and ionic strengths lead to a full set of thermodynamicbinding constants together with the enthalpies and entropies of binding. The adsorption of HSA onto SPBs is described with a two-step model. The free energy of binding Delta Gb depends only weakly on temperature because of a marked compensation of enthalpy by entropy. Studies of the adsorbed HSA by Fourier transform infrared spectroscopy (FT-IR) demonstrate no significant disturbance in the secondary structure of the protein. The quantitative analysis demonstrates that counterion release is the major driving force for adsorption in a process where proteins become multivalent counterions of the polyelectrolyte chains upon adsorption. A comparison with the analysis of other sets of data related to the binding of HSA to polyelectrolytes demonstrates that the cancellation of enthalpy and entropy is a general phenomenon that always accompanies the binding of proteins to polyelectrolytes dominated by counterion release.
KW  - ITC
KW  - spherical polyelectrolyte brushes
KW  - enthalpy-entropy compensation (EEC)
KW  - proteins
KW  - thermodynamics
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-517307
SN  - 1866-8372
IS  - 1
ER  - 
TY  - GEN
A1  - Wessig, Pablo
A1  - Hille, Carsten
A1  - Kumke, Michael Uwe
A1  - Meiling, Till Thomas
A1  - Behrends, Nicole
A1  - Eisold, Ursula
T1  - Two-photon FRET pairs based on coumarin and DBD dyes
N2  - The synthesis and photophysical properties of two new FRET pairs based on coumarin as a donor and DBD dye as an acceptor are described. The introduction of a bromo atom dramatically increases the two-photon excitation (2PE) cross section providing a 2PE-FRET system, which is also suitable for 2PE-FLIM.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 318 
KW  - resonance energy-tansfer
KW  - conformational-changes
KW  - microscopy
KW  - proteins
KW  - acid
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-394445
SP  - 33510
EP  - 33513
ER  -