Our Research:

The group focuses on the structure and dynamics of soft matter in biological systems. More specifically we study the structure and dynamics of intrinsically disordered proteins, the structure and formation of asymmetric lipid membranes and the structure of neuronal connection in brain slices.

A large class of proteins lacks a defined tertiary structure, with structured parts (or not) connected by disordered regions with high configurational freedom. This challenges the traditional structure-function paradigm. IDPs sometimes fold upon binding to an active configuration, e.g., with other molecules. Understanding their dynamics is crucial for grasping the structuring process prior to function, the dynamics of folding, or their function as unstructured proteins. Two approaches can elucidate this phenomenon: unfolding structured proteins (e.g., by temperature, pressure, or chemically) to examine stable intermediates and transition regions or observing intrinsically unfolded proteins. Completely unstructured proteins behave like stiff random polymer chains. Structure and dynamics are influenced by geometrical restrictions, such as remaining disulfide bonds, charges on the amino acid strand, or stiffer regions with preserved secondary structure. In the group we use Neutron-Spin-Echo, SANS and SAXS to probe the structure and dynamics of this class of proteins.

The myelin sheath’s lipid membrane bilayers, spaced ~15nm apart, produce a distinct signal in the SAXS regime. This signal helps us ascertain the myelin concentration, 3D orientation, average bilayer count around axons, and other structural features within the examined volume.3D-scanning SAXS operates by mapping a thin slice (30-60µm) of fixed brain tissue at a resolution between 50 and 5µm, under various tilt angles relative to the probing beam. By combining signals from the same volume element probed at different tilt angles, we can determine the primary 3D direction of nerve fibers in that volume element. This method allows us to integrate nanometer-scale information with micrometer-scale mapping for samples spanning several cm². Our team is striving to quantitatively correlate our findings with a faster technique used at INM-1 by Markus Axer’s group, known as 3D-PLI.