Van der Waals colloquium by prof.dr. Nynke Dekker from Delft University of Technology (Netherlands) on "Adventures in DNA replication using single-molecule biophysics". Nynke’s lab investigates by biophysical and biochemical studies the key cellular processes of DNA and RNA replication, in vitro and in vivo.

Abstract: Many transactions on DNA are carried out by molecular machines that operate at the nanometer-scale. How they do so effectively is a question of long-standing interest. We are particularly interested in studying the dynamics of these molecular machines using single-molecule techniques. I will briefly highlight how the field of single-molecule biophysics has advanced such techniques over the past decades, allowing the dynamics of diverse motor proteins to be accurately followed.

I will next describe how single-molecule techniques are being used to tackle new challenges, including the probing of complex molecular machines built up from many different components. The replisome that copies DNA is such a complex machine. While the overall outline of replisome assembly in eukaryotes such as ourselves is understood, little is known about the dynamics of the individual proteins on the DNA and how these contribute to the formation of proper replisomes. I will show that using integrated optical trapping and confocal microscopy, one can dissect how protein binding, diffusion, sequence recognition, and protein-protein interactions play important roles in replisome assembly. And I will then describe how we can now follow the motion of the replicative helicase, and close by presenting an outlook for the future.

The Joan van der Waals colloquium is an ongoing bi-weekly lecture series, organized by LION. As all speakers are instructed to give an accessible lecture for everyone, these lectures aid in getting a broader view of physics. Each colloquium is preceded by an opening act: a PhD student or postdoc from LION and a different field than the invited speaker, to give a 10-min presentation. After the colloquium, there is a chance to meet your colleagues and participate in discussions at the borrel. More information can be found here.