Proteins are fascinating examples of self-organized molecular machines. Without any help a polypeptide strand can fold into functional three-dimensional structures. We are interested in studying the function and folding process of proteins on the single molecule level

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Cells can respond to mechanical forces, thanks to sophisticated measuring systems. The cell cytoskeleton rearranges accordingly to external mechanical stimuli, ultimately affecting cell growth and differentiation. Many different proteins cooperate to hold together the cytoskeleton and to connect it to the cell membrane and organelles, but the detailed molecular mechanisms of force transduction are largely unexplored. more >>

The formation of protein structures is still a puzzling question. The first theories were developed 55 years ago, when Anfinsen et al. demonstrated that proteins can fold by themselves 1. Additionally, Levinthal and coworkers suggested that an amino acid chain can adapt a high number of possible folds and random searching through the many possible conformations could never happen in a reasonable folding time 2. Proteins are indeed able to fold on a time scale of milliseconds, which led Levinthal and coworkers to the conclusion that proteins follow a programmed structure formation pathway. more >> 

 

Proteins are fundamentally important to life, since they perform all of functions within living organisms. It is the protein’s structure that defines its biological function within a cell, however, protein function is a dynamical process. Therefore, to understand completely how a protein functions, we must also understand how it moves.

Using single molecule measurements of proteins, it is possible to directly observe and manipulate protein motions, and to study how they are influenced by interactions with other molecules. From such experiments, the rates of folding, unfolding, association and dissociation as well as stabilities of the proteins under different conditions can also be found. more >>

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Due to momentum conservation it is possible to trap microscopic particles using sharply focused laser beams. The object trapped in the laser focus obeys Hooke’s law, where the restoring force felt by the object is linear to its displacement from the trap centre. Thus, the focused laser beam can be seen as a spring for microscopic objects. more >>