2011, Wang, C., Neugebauer, U., Bürck, J., Myllykoski, M., Baumgärtel, P., Popp, J., Kursula, P.

As an essential structural protein required for tight compaction of the central nervous system myelin sheath, myelin basic protein (MBP) is one of the candidate autoantigens of the human inflammatory demyelinating disease multiple sclerosis, which is characterized by the active degradation of the myelin sheath. In this work, recombinant murine analogues of the natural C1 and C8 charge components (rmC1 and rmC8), two isoforms of the classic 18.5-kDa MBP, were used as model proteins to get insights into the structure and function of the charge isomers. Various biochemical and biophysical methods such as size exclusion chromatography, calorimetry, surface plasmon resonance, small angle X-ray and neutron scattering, Raman and fluorescence spectroscopy, and conventional as well as synchrotron radiation circular dichroism were used to investigate differences between these two isoforms, both from the structural point of view, and regarding interactions with ligands, including calmodulin (CaM), various detergents, nucleotide analogues, and lipids. Overall, our results provide further proof that rmC8 is deficient both in structure and especially in function, when compared to rmC1. While the CaM binding properties of the two forms are very similar, their interactions with membrane mimics are different. CaM can be used to remove MBP from immobilized lipid monolayers made of synthetic lipids - a phenomenon, which may be of relevance for MBP function and its regulation. Furthermore, using fluorescently labelled nucleotides, we observed binding of ATP and GTP, but not AMP, by MBP; the binding of nucleoside triphosphates was inhibited by the presence of CaM. Together, our results provide important further data on the interactions between MBP and its ligands, and on the differences in the structure and function between MBP charge isomers.

2015, Friebe, Nadine, Schreiter, Katja, Kübel, Joachim, Dietzek, Benjamin, Moszner, Norbert, Burtscher, Peter, Oehlke, Alexander, Spange, Stefan

A series of para-substituted acetophenones bearing a furanyl or a thiophenyl moiety show a large Stokes-shift, which is a function of various solvent properties. Photophysical properties such as emission lifetime of the compounds have been determined using time-correlated-single photon counting to secure the intrinsic fluorescence behaviour. The solvent dependent position of the UV/Vis emission band [small nu, Greek, tilde]max,em of the compounds has been measured in 26 various solvents. The influence of the solvent on [small nu, Greek, tilde]max,em is of very complex nature and mathematically analysed by multiple square linear solvation energy (LSE)-correlation analysis using Catalán's four-solvent parameter set. Solvent acidity has a strong influence on the bathochromic shift of 2,5-disubstituted furan derivatives compared to the non-5-substituted furan and thiophene derivatives, which show a contrary behaviour. Therefore, the 5-cyanofuranyl-substituted acetophenone derivative is useful as a probe for measuring environmental properties by fluorescence spectroscopy.