Unser 10. Leibniz Plant Biochemistry Symposium am 7. und 8. Mai war ein großer Erfolg. Thematisch ging es in diesem Jahr um neue Methoden und Forschungsansätze der Naturstoffchemie. Die exzellenten Vorträge über Wirkstoffe…
Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
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…
The reaction of the dinuclear platina-β-diketone [Pt2{(COMe)2H}2(μ-Cl)2] (1) with two equivalents of adenine and its methylated derivatives N6-R,9-R′Ade–H resulted in adenine-based aminocarbene platinum(II) complexes [Pt(COMe)Cl{CMe(N6-R,9-R′Ade–H)-κC,κN}] (R/R′ = Me/Me, 2; H/Me, 3; H/H, 4) whose identities were confirmed by NMR and IR spectroscopies as well as by high-resolution mass spectrometric investigations. Single-crystal X-ray diffraction analyses of complexes 2 and 4·THF revealed relatively short Pt–C and N–C bonds in the aminocarbene–platinum units, which is in accord with a substantial double bond character of these bonds. The electronic structure of these complexes will be further confirmed by DFT calculations as also the course of reaction.
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.
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.