How helices bend, curve and stretch: does physical intuition help us understand protein mechanics?

Our group is investigating the mechanics of a key structural protein, collagen, which is comprised of three chains that coil to make a triple helix. Collagen is the fundamental structural protein in vertebrates and is widely used as biomaterial, for example as a substrate for tissue engineering. In spite of its prevalence and mechanical importance in biology, the mechanics of collagen is surprisingly unresolved. In this talk, I will focus on its flexibility and its stress response, why these properties are important and contentious, and how my group’s work has helped to address some of the discrepancies in the literature. I’ll describe our experimental approaches, which use image-analysis software and statistics to analyse atomic-force microscopy images of single collagen proteins, and which use a high-throughput single-molecule force spectroscopy instrument we’ve built, the mini-radio centrifuge force microscope (MR.CFM), to measure collagen’s response to load. Finally, we will see whether physical intuition and models correctly predict the mechanical response of this key protein.