Research

We are interested in conformational dynamics of biomolecules. In particular, we study (membrane) protein folding, protein-DNA interactions during DNA replication and recombination and regulatory DNA and RNA conformations.

Cells constantly react to environmental challenges by efficient and rapid adaptation. This adaptive process is mastered by enzymes, which are often located on the periphery of the cell or near the genome. Here, they play a key role in processing information, as they undergo conformational changes and thereby activate or silence other enzymes. Our lab is interested in providing a mechanistic understanding of conformational changes during molecular structure formation (e.g. protein folding, DNA secondary structure formation) and intermolecular interactions and competitions, e.g. receptor ligand interactions or competion of enzymes for similar DNA targets. All these observations are supported by continuous development of cutting-edge single-molecule instrumentations. 

A prominent interface between physics and biology is the field of microscopy. Over the past centuries, advances in light microscopy have often enabled a closer look on biological questions, while at the same time questions arising from biology have inspired technical or conceptual improvements for microscopy. Challenges like synchronization or heterogeneity can now be mastered by a set of different single-molecule methods, which have raised new questions from biology and inspired further development of instrumentation and assays. Our lab works at the interface of biophysical method development and molecular biology, where the unique combination of expertise present in the team helps to realize our long-term vision: painting an experimentally-based, dynamic portrait of the living cell with maximum resolution - single molecule, single event, (sub)nanometer and pico-Newton accuracy.

Please follow the links to learn more about each subproject.

(Membrane) Protein folding 

Protein folding is a process of molecular self-assembly during which a disordered polypeptide chain collapses to form a compact and well-defined three-dimensional structure. Here, we use optical tweezers and single-molecule FRET to track conformations of fast folding proteins and membrane proteins along their paths on the multi-dimensional energy landscape. Read more

Collaborators: Sandro Keller (Kaiserslautern), Charles Deber (Toronto)

Protein - DNA interactions

Protein-DNA interactions are the key for cell regulation, including cell division and adaptation. There are different levels of specificity for these interactions ranging from unspecific single-stranded DNA binding to specific secondary structure recognition. We use single-molecule FRET, FCS and magnetic tweezers to study the conformations and kinetics of protein DNA interactions. Read more

Collaborators: Didier Mazel (Paris), Silvia Ayora (Madrid)

DNA and RNA secondary structures

DNA and RNA are known to form secondary structures, e.g. hairpins, if self-complementary sequences are present. RNA secondary structures have evolved as expression controls (riboswitches) and DNA secondary structures are used as recombination sites (Integron). Here, we study the structure and conformational kinetics of RNA and DNA hairpin structures.

Collaborators: Didier Mazel (Paris), Simon Ebbinghaus (Bochum)

Protein-based biomineralization

Diatoms have evolved an intricate biosilica cell wall with a structural precision ranging from micrometers down to a few nanometers. Current models assume an underlying protein-based structure for subsequent biomineralization. We use single-molecule localisation microscopy to image the underlying protein patterns with up to 20 nm resolution. Read more

Collaborators: Research Unit Nanomee, Nils Kröger (Dresden)