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…
Faden, F.; Mielke, S.; Lange, D.; Dissmeyer, N.;Generic tools for conditionally altering protein abundance and phenotypes on demandBiol. Chem.395737-762(2014)DOI: 10.1515/hsz-2014-0160
Conditional gene expression and modulating protein stability under physiological conditions are important tools in biomedical research. They led to a thorough understanding of the roles of many proteins in living organisms. Current protocols allow for manipulating levels of DNA, mRNA, and of functional proteins. Modulating concentrations of proteins of interest, their post-translational processing, and their targeted depletion or accumulation are based on a variety of underlying molecular modes of action. Several available tools allow a direct as well as rapid and reversible variation right on the spot, i.e., on the level of the active form of a gene product. The methods and protocols discussed here include inducible and tissue-specific promoter systems as well as portable degrons derived from instable donor sequences. These are either constitutively active or dormant so that they can be triggered by exogenous or developmental cues. Many of the described techniques here directly influencing the protein stability are established in yeast, cell culture and in vitro systems only, whereas the indirectly working promoter-based tools are also commonly used in higher eukaryotes. Our major goal is to link current concepts of conditionally modulating a protein of interest’s activity and/or abundance and approaches for generating cell and tissue types on demand in living, multicellular organisms with special emphasis on plants.
Publikation
Barroso, S.; Coelho, A. M.; Gómez-Ruiz, S.; Calhorda, M. J.; Žižak, ?.; Kaluđerović, G. N.; Martins, A. M.;Synthesis, cytotoxic and hydrolytic studies of titanium complexes anchored by a tripodal diamine bis(phenolate) ligandDalton Trans.4317422-17433(2014)DOI: 10.1039/C4DT00975D
The reactivity, cytotoxic studies and hydrolytic behaviour of diamine bis(phenolate) titanium complexes are reported. The reactions of [Ti(tBu2O2NN′)Cl]2(μ-O) (1) with LiOiPr or HOiPr in the presence of NEt3, aiming at the synthesis of the alkoxido derivative of 1 led to no reaction or to the synthesis of the monomeric complex [Ti(tBu2O2NN′)(OiPr)2] (3), respectively. A small amount of the alkoxidotitanium dimer [Ti(tBu2O2NN′)(OiPr)]2(μ-O) (2) crystallized out of a solution of 3 and DFT calculations showed that the transformation of 1 into 3 is a thermodynamically favorable process in the presence of a base (NEt3) (ΔG = −14.7 kcal mol−1). 2 was quantitatively obtained through the direct reaction of the ligand precursor H2(tBu2O2NN′) with titanium tetra(isopropoxido). Further reaction of 2 with an excess of TMSCl was revealed to be the most suitable method for the preparation of [Ti(tBu2O2NN′)Cl2] (4). 1 and 3 disclosed cytotoxic activity towards HeLa, Fem-x, MDA-MB-361 and K562 cells and 1 exhibited moderate binding affinity to FS-DNA. 1H NMR hydrolysis studies attested the fast decomposition of 4 in the presence of D2O. The hydrolysis of 3 is slower and proceeds through the formation of [Ti(tBu2O2NN′)(OH)]2(μ-O) (5) that was crystallographically characterized. Upon D2O addition 1 immediately forms complex new species, stable in solution for long periods (weeks).