TY  - JOUR
A1  - Janzen, Dieter
A1  - Slavik, Benedikt
A1  - Zehe, Markus
A1  - Sotriffer, Christoph
A1  - Loos, Helene M.
A1  - Buettner, Andrea
A1  - Villmann, Carmen
T1  - Sesquiterpenes and sesquiterpenoids harbor modulatory allosteric potential and affect inhibitory GABA\(_{A}\) receptor function in vitro
JF  - Journal of Neurochemistry
N2  - Naturally occurring compounds such as sesquiterpenes and sesquiterpenoids (SQTs) have been shown to modulate GABA\(_{A}\) receptors (GABA\(_{A}\)Rs). In this study, the modulatory potential of 11 SQTs at GABA\(_{A}\)Rs was analyzed to characterize their potential neurotropic activity. Transfected HEK293 cells and primary hippocampal neurons were functionally investigated using electrophysiological whole-cell recordings. Significantly different effects of β-caryophyllene and α-humulene, as well as their respective derivatives β-caryolanol and humulol, were observed in the HEK293 cell system. In neurons, the concomitant presence of phasic and tonic GABA\(_{A}\)R configurations accounts for differences in receptor modulation by SQTs. The in vivo presence of the γ\(_{2}\) and δ subunits is important for SQT modulation. While phasic GABA\(_{A}\) receptors in hippocampal neurons exhibited significantly altered GABA-evoked current amplitudes in the presence of humulol and guaiol, negative allosteric potential at recombinantly expressed α\(_{1}\)β\(_{2}\)γ\(_{2}\) receptors was only verified for humolol. Modeling and docking studies provided support for the binding of SQTs to the neurosteroid-binding site of the GABA\(_{A}\)R localized between transmembrane segments 1 and 3 at the (\(^{+}\)α)-(\(^{-}\)α) interface. In sum, differences in the modulation of GABA\(_{A}\)R isoforms between SQTs were identified. Another finding is that our results provide an indication that nutritional digestion affects the neurotropic potential of natural compounds.
KW  - allosteric modulation
KW  - GABA\(_{A}\) receptor
KW  - patch clamp recording
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259546
VL  - 159
IS  - 1
ER  - 
TY  - JOUR
A1  - Bothe, Sebastian
A1  - Hänzelmann, Petra
A1  - Böhler, Stephan
A1  - Kehrein, Josef
A1  - Zehe, Markus
A1  - Wiedemann, Christoph
A1  - Hellmich, Ute A.
A1  - Brenk, Ruth
A1  - Schindelin, Hermann
A1  - Sotriffer, Christoph
T1  - Fragment screening using biolayer interferometry reveals ligands targeting the SHP-motif binding site of the AAA+ ATPase p97
JF  - Communications Chemistry
N2  - Biosensor techniques have become increasingly important for fragment-based drug discovery during the last years. The AAA+ ATPase p97 is an essential protein with key roles in protein homeostasis and a possible target for cancer chemotherapy. Currently available p97 inhibitors address its ATPase activity and globally impair p97-mediated processes. In contrast, inhibition of cofactor binding to the N-domain by a protein-protein-interaction inhibitor would enable the selective targeting of specific p97 functions. Here, we describe a biolayer interferometry-based fragment screen targeting the N-domain of p97 and demonstrate that a region known as SHP-motif binding site can be targeted with small molecules. Guided by molecular dynamics simulations, the binding sites of selected screening hits were postulated and experimentally validated using protein- and ligand-based NMR techniques, as well as X-ray crystallography, ultimately resulting in the first structure of a small molecule in complex with the N-domain of p97. The identified fragments provide insights into how this region could be targeted and present first chemical starting points for the development of a protein-protein interaction inhibitor preventing the binding of selected cofactors to p97.
KW  - fragment screening
KW  - AAA+ ATPase p97
KW  - biosensor
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300821
VL  - 5
IS  - 1
ER  - 
TY  - JOUR
A1  - Schmidt, Sebastian
A1  - Zehe, Markus
A1  - Holzgrabe, Ulrike
T1  - Characterization of binding properties of ephedrine derivatives to human alpha-1-acid glycoprotein
JF  - European Journal of Pharmaceutical Sciences
N2  - Most drugs, especially those with acidic or neutral moieties, are bound to the plasma protein albumin, whereas basic drugs are preferentially bound to human alpha-1-acid glycoprotein (AGP). The protein binding of the long-established drugs ephedrine and pseudoephedrine, which are used in the treatment of hypotension and colds, has so far only been studied with albumin. Since in a previous study a stereoselective binding of ephedrine and pseudoephedrine to serum but not to albumin was observed, the aim of this study was to check whether the enantioselective binding behavior of ephedrine and pseudoephedrine, in addition to the derivatives methylephedrine and norephedrine, is due to AGP and to investigate the influence of their different substituents and steric arrangement. Discontinuous ultrafiltration was used for the determination of protein binding. Characterization of ligand-protein interactions of the drugs was obtained by saturation transfer difference nuclear magnetic resonance spectroscopy. Docking experiments were performed to analyze possible ligand-protein interactions. The more basic the ephedrine derivative is, the higher is the affinity to AGP. There was no significant difference in the binding properties between the individual enantiomers and the diastereomers of ephedrine and pseudoephedrine.
KW  - protein binding
KW  - AGP
KW  - ultrafiltration
KW  - saturation transfer difference NMR
KW  - epitope mapping
KW  - ephedrine
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300848
VL  - 181
ER  -