Protein folding
We are examining protein folding and unfolding characteristics by the use of fluorescent markers. In collaboration with Prof. Hartl, we examine the functionality of chaperonin-assisted protein folding in detail. The GroEL/GroES system from E. coli works as a container (GroEL) with a lid (GroES). In a current project, Maltose binding protein (MBP) was chosen as a substrate and labeled with two fluorescent dyes at carefully selected labeling positions. In spFRET experiments the folding state of MBP and the influence of the chaperonin-system were observed by monitoring the FRET efficiency. Different mutants of the GroEL/GroES system were examined to clarify its working mechanism.
![GroEl action](pics/folding_pic.gif)
In collaboration with the group of Prof. Buchner, we study the folding and unfolding pathways of different immunoglobulin (Ig) antibody domains and their interaction with each other. By labeling a protein with two different fluorescent dyes at different labeling positions, the dyes will undergo FRET. The FRET efficiency E depends on the spatial distance of the dyes, thus indicating the folding state of the protein. At the same time, a third fluorescent marker attached to a different Ig-domain enables us to determine the colocalization and thereby the fusion of the domains using PIE-FCCS.