For all organisms populating the Earth, motion is synonymous with life. In the living cell, protein molecules - its most important building blocks and work horses - are constantly on the move.... Show moreFor all organisms populating the Earth, motion is synonymous with life. In the living cell, protein molecules - its most important building blocks and work horses - are constantly on the move. Traditional static models are no longer sufficient for a thorough description of interactions among these biomolecules. Here we present a direct, experimental approach for assessing the dynamics of interactions between proteins, which for a long time has been an exclusive realm of theoretical studies. Show less