Our research group is interested in proteins that require transition metal-containing cofactors for their catalytic function. We use structural biology, biochemistry, and biophysical methods to understand the molecular bases of living processes. The incorporation of cofactors such as metal ions or metal clusters into the active site of proteins leads to exiting chemistry with incredible specificity. The combination of transition metal reactivity with the highly selective protein environment makes the field of bioinorganic chemistry extremely exciting.
A particular focus is to understand the role of iron-sulfur proteins in challenging biotransformations. Iron-sulfur clusters are among the most ancient and versatile inorganic cofactors in nature and are involved in a large number of conserved cellular processes. They can perform a wide range of functions, from electron transfer to redox and non-redox catalysis. We are investigating the structure and function relationship of iron-sulfur proteins that are involved in biosynthesis of natural products or essential cellular processes. We are also interested in exploring the catalytic potential of biohybrid systems based on native metalloproteins. The projects in my laboratory cover a wide range from DNA to protein structure and function.
If you are interested in a Bachelor or Master project, please contact me by email:
If you are interested in bioinorganic chemistry and metalloproteins, visit the Nature website and listen to the podcast Insight:Metalloproteins
The elucidation of the three-dimensional structure of a protein in its native form enables us to understand the mechanism of the reaction performed by this protein. The crystal structure also provides information about the cofactor and the geometry in the active site of the protein. X-ray diffraction of single crystals is used to determine the structure of a protein. Therefore, single crystals of pure, homogeneous protein samples have to be obtained. We perform all the steps from the first crystallization screens to data collection at the synchrotron, data processing and model building.
Characterization of the cofactors
In addition to structure-based studies we are also interested in characterizing the metal-containing cofactors. When working with iron-sulfur proteins, it is crucial to protect the cluster from oxidation by oxygen, which leads to decomposition of the cofactor. Therefore, experiments have to be carried out in an anaerobic environment provided by a glovebox. Iron-sulfur clusters and other metal-containing cofactors exhibit features in the visible region of a UV/VIS spectrum. Thus, electronic absorption spectroscopy is a powerful tool for the identification and characterization of these metalloproteins. The metal content can also be investigated using inductively coupled plasma mass spectrometry, which indicated the amount of metal that is bound to the protein.
Molecular biological and biochemical methods
We apply a broad spectrum of methods to get from gene to structure and function. Molecular biological techniques are used to generate expression constructs and to introduce mutations into the target gene. Cloning of different variants with different lengths can increase the chances of obtaining crystals. Exchanging one or more amino acids can provide valuable information about the mechanism of enzymatic reactions. Expression conditions and the protocol for protein purification have to be established and optimized to maximize the yield of functional protein. A high purity and homogeneity of the protein sample are prerequisites for analytical and crystallographic studies. Thus, we apply multiple chromatography steps for the preparation of high quality samples.
Insights into the Binding of Pyridines to the Iron-Sulfur Enzyme IspH
I. Span, K. Wang, W. Eisenreich, A. Bacher, Y. Zhang, E. Oldfield, M. Groll, J. Am. Chem. Soc. 2014, 136 (22), 7926-32.
Structures of fluoro, amino, and thiol inhibitors bound to the [Fe4S4] protein IspH
I. Span, K. Wang, W. Wang, J. Jauch, W. Eisenreich, A. Bacher, E. Oldfield, M. Groll, Angew. Chem. Int. Edit. 2013, 52 (7), 2118-21.
Discovery of acetylene hydratase activity of the iron-sulphur protein IspH
I. Span, K. Wang, W. Wang, Y. Zhang, A. Bacher, W. Eisenreich, K. Li, C. Schulz, E. Oldfield, M. Groll, Nat. Commun. 2012, 3, 1042.