Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Seit Februar 2021 bietet Wolfgang Brandt, ehemaliger Leiter der Arbeitsgruppe Computerchemie am IPB, sein Citizen Science-Projekt zur Pilzbestimmung an. Dafür hat er in regelmäßigen Abständen öffentliche Vorträge zur Vielfalt…
Changes in cellular calcium levels are one of the earliest signalling events in plants exposed to pathogens or other exogenous factors. In a genetic screen, we identified an Arabidopsis thaliana ‘changed calcium elevation 1 ’ (cce1 ) mutant with attenuated calcium response to the bacterial flagellin flg22 peptide and several other elicitors. Whole genome re‐sequencing revealed a mutation in ALG12 (Asparagine‐Linked Glycosylation 12 ) that encodes the mannosyltransferase responsible for adding the eighth mannose residue in an α‐1,6 linkage to the dolichol‐PP‐oligosaccharide N ‐glycosylation glycan tree precursors. While properly targeted to the plasma membrane, misglycosylation of several receptors in the cce1 background suggests that N ‐glycosylation is required for proper functioning of client proteins.
Publikation
Gómez-Ruiz, S.; Žižak, ?.; Kaluđerović, G. N.;Structural studies and cytotoxic activity against human cancer cell lines of mono and dinuclear tin(IV) complexes with the α,α′-dimercapto-o-xylene ligandInorg. Chim. Acta423117-122(2014)DOI: 10.1016/j.ica.2014.04.023
The reaction of α,α′-dimercapto-o-xylene (H2dmox) with SnPh2Cl2 (1:1) and SnPh3Cl (1:2) in the presence of two equivalents of NEt3 led to the formation of the complexes [SnPh2(dmox)] (1) and [SnPh3(μ-dmox)]2 (2), respectively. Both complexes have been characterized by multinuclear NMR and IR spectroscopy, mass spectrometry and elemental analysis. In addition, the molecular structure of complex 2 has been determined by single crystal X-ray diffraction studies. The cytotoxic activity of 1 and 2 was tested against the tumor cell lines human cervix adenocarcinoma HeLa, breast carcinoma MDA-MB-453, colon carcinoma LS174 and human myelogenous leukemia K562. In addition, the toxicity of both complexes to non-stimulated and stimulated peripheral blood mononuclear cells (PBMC) has been tested. The in vitro cytotoxicity tests show very high antiproliferative activity of both complexes, being much higher that of 2. In addition, this compound shows a higher cytotoxic activity towards cancer cell lines than to non-stimulated and stimulated PBMC, indicating a slight selectivity to cancer cell lines.
Publikation
Wils, C. R.; Brandt, W.; Manke, K.; Vogt, T.;A single amino acid determines position specificity of an Arabidopsis thaliana CCoAOMT-like O-methyltransferaseFEBS Lett.587683-689(2013)DOI: 10.1016/j.febslet.2013.01.040
Caffeoyl‐coenzyme A O‐methyltransferase (CCoAOMT)‐like proteins from plants display a conserved position specificity towards the meta‐position of aromatic vicinal dihydroxy groups, consistent with the methylation pattern observed in vivo. A CCoAOMT‐like enzyme identified from Arabidopsis thaliana encoded by the gene At4g26220 shows a strong preference for methylating the para position of flavanones and dihydroflavonols, whereas flavones and flavonols are methylated in the meta‐position. Sequence alignments and homology modelling identified several unique amino acids compared to motifs of other CCoAOMT‐like enzymes. Mutation of a single glycine, G46 towards a tyrosine was sufficient for a reversal of the unusual para‐ back to meta‐O‐methylation of flavanones and dihydroflavonols.
Publikation
Solé, M.; Brandt, W.; Arnold, U.;Striking stabilization of Rana catesbeiana ribonuclease 3 by guanidine hydrochlorideFEBS Lett.587737-742(2013)DOI: 10.1016/j.febslet.2013.01.056
Unfolding by chemical denaturants and the linear extrapolation method are widely used to determine the free energy of proteins. Ribonuclease 3 from bullfrog shows an extraordinary behavior in guanidinium hydrochloride in comparison to its homologues ribonuclease A and onconase with a high transition midpoint of denaturation but an apparently low cooperativity. The analysis of the interdependence of thermal, urea‐, and guanidine hydrochloride‐induced unfolding revealed that whereas addition of urea resulted in the expected destabilization of all three proteins, guanidine hydrochloride acted diversely: in contrast to ribonuclease A and onconase, both of which were destabilized as expected, low concentrations of guanidine hydrochloride significantly stabilize ribonuclease 3 from bullfrog. This stabilizing effect was endorsed by in silico docking studies.