plant metallothioneins; cyclic proteins; spectroscopy; X-ray crystallography; metal-thiolate clusters; bioinorganic chemistry; nucleic acids; site specific nucleobase modifications; DNA-templated synthesis
Egloff David, Oleinich Igor A., Zhao Meng, König Sebastian L. B., Sigel Roland K. O., Freisinger Eva (2016), Sequence-specific post-synthetic oligonucleotide labeling for single-molecule fluorescence applications, in ACS Chem. Biol.
, 11, 2558-2567.
Tarasava Katsiaryna, Freisinger Eva (2015), Investigating the influence of histidine residues on the metal ion binding ability of the wheat metallothionein g-Ec-1 domain, in J. Inorg. Biochem.
, 153, 197-203.
Egloff David, Oleinich Igor A., Freisinger Eva (2015), Sequence-specific generation of 1,N6-ethenoadenine and 3,N4-ethenocytosine in single-stranded unmodified DNA, in ACS Chem. Biol.
, 10, 547-553.
Tarasava Katsiaryna, Freisinger Eva (2014), An optimized intein-mediated protein ligation approach for the efficient cyclization of cysteine-rich proteins, in Protein Eng. Des. Sel.
, 27, 481-488.
Freisinger Eva, Vašák M. (2013), Cadmium in metallothioneins, in Sigel Astrid, Sigel Helmut (ed.), Springer, Dordrecht, 339-371.
Wan X., Schicht O., Freisinger E. (2013), Cu(I) coordination by two plant metallothioneins, in Z. Anorg. Allg. Chem.
, 639, 1365-1369.
Tarasava Katsiaryna, Johannsen Silke, Freisinger Eva (2013), Solution structure of the circular g-domain analog from the wheat metallothionein Ec-1, in Molecules
, 18, 14414-14429.
Huber T., Freisinger E. (2013), Sulfide ions as modulators of metal-thiolate cluster size in a plant metallothionein, in Dalton Trans.
, 42, 8878-8889.
Wan X., Freisinger E. (2012), Incorporation of sulfide ions into the cadmium(II) thiolate cluster of, in Inorg. Chem.
, 52, 785-792.
Donghi D., Johannsen S., Sigel R. K. O., Freisinger E. (2012), NMR spectroscopy in bioinorganic chemistry, in Chimia
, 66, 791-797.
Phongtongpasuk S., Paulus S., Schnabl J., Sigel R. K. O., Spingler B., Hannon M. J., Freisinger E., Binding of a designed anti-cancer drug to the heart of an RNA three-way junction, in Angew. Chem. Int. Ed.
Peroza E. A., Cabral A. C. S, Wan X., Freisinger E., Metal ion release from metallothioneins: Proteolysis as an alternative to oxidation, in Metallomics
Loebus J., Leitenmaier B., Meissner D., Braha B., Krauss G.-J., Dobritzsch D., Freisinger E., The major function of a metallothionein from the aquatic fungus Heliscus lugdunensis is cadmium detoxification, in J. Inorg. Biochem.
This proposal is divided into two, largely independent projects: Project A focuses on the structures and properties of plant metallothioneins (MTs). A subproject will also investigate cyclic MT forms. The tight regulation of reactive transition metal ions is essential to impede side reactions and cellular damage. One protein superfamily that is taking part in the uptake, transport, and regulation of metal ions within the cell are the MTs, small Cys-rich proteins with the ability to coordinate metal ions with the electron configuration d10 in form of metal clusters. MTs from plants have been scarcely studied so far. In this project we are investigating members of each of the four plant MT subfamilies. We apply mostly spectroscopic techniques such as UV/vis, CD, and atomic absorption spectroscopy coupled with chromatographic techniques for separation and identification purposes, but also more elaborate methods such as EXAFS or PAC spectroscopy are used. Very important for our research is also mass spectrometry. Further, NMR spectroscopy enables us to study metal ion binding affinities or coordination environments of metal ions, and can be used to determine 3D structures. The latter we also try to achieve with crystallographic techniques. These experiments are complemented with functional studies to draw conclusions about the possible roles of plant MTs in vivo. We look at metal ion release under specific conditions, investigate the properties of our proteins in yeast cells as a model system for eukaryotic cells, and even analyse protein expression pattern of a wheat grain specific MT directly in the seed.In project B we are performing site-specific modifications of larger nucleic acids with a DNA-templated approach. We design and synthesize specific reactive groups that are able to generate the desired modification. By coupling these reactive groups to a short complementary oligonucleotide sequence we position them directly opposite the nucleotide to be modified and in this way achieve the desired site-specificity. On the one hand, modifications are introduced that are known mutagenic lesions occurring naturally in DNA such as ?-adducts of bases, oxidized guanine at the C8 position or UV light-induced photo-adducts. Such specifically modified nucleic acids are important for, e.g., biochemical studies of nucleotide repair mechanisms or to monitor the fidelity of polymerases in performing translesional synthesis. In addition we are attempting to introduce functional groups at the N4 position of cytosine bases, which can be used for specific labelling purposes such as the attachment of fluorophores. Our studies are hence important for researchers from the fields of Biochemistry, Structural Biology, Biophysics, and from the Nanosciences alike.