Karen N. Allen talks about what she considers to be the major challenges of a successful investigation of protein structure–function relationships. She emphasizes the intricate connection between the motion of enzymes and their catalysis. This, in turn, necessitates the employment of techniques that capture the motion of the protein and are able to correlate the gathered data with the chemistry. Karen N. Allen is a professor at the Department of Chemistry of the Boston University in Massachusetts. Her research is focused on various aspects of protein structure and function.