Regensburg 2019 – wissenschaftliches Programm
CPP 24: Focus: Mechanoresponsive Molecules and Materials - organized by Kerstin Blank and Robert Göstl
CPP 24.2: Hauptvortrag
Dienstag, 2. April 2019, 11:30–12:00, H14
Mechanoradicals in collagen or: Why playing soccer hurts — •Frauke Gräter1,2, Christopher Zapp1,2, Agnieszka Obarska-Kosinski1, Csaba Daday1, and Reinhard Kappl3 — 1HITS, Heidelberg, Germany — 2Interdisciplinary Center for Scientific Computing, Heidelberg University, Germany — 3Medical Center of Saarland, Homburg, Germany
Polymers subjected to mechanical stress - be it a shoe sole or rubber band - generate mechanoradicals by undergoing homolytic bond scission. The existence, nature and mode of action of mechanoradicals formed in protein materials under physiological levels of loading, are fully unknown. I will present our recent results on mechanoradicals in collagen. Electron-paramagnetic resonance (EPR) spectroscopy of stretched rat tail tendon fascicles in conjunction with atomistic Molecular Dynamics simulations of collagen I model fibrils show that the radicals form by bond scission in the direct vicinity of crosslinks along the fiber. Radicals then migrate to the adjacent clusters of aromatic residues where they are stabilized. They finally convert into hydrogen peroxide, a key redox signaling molecule. Our work proposes protein mechanoradicals as a yet undiscovered source of oxidative stress, with potential links to processes such as pain sensation and inflammation. Being exposed to extreme loads, collagen I evolved as a radical sponge, a defense against mechano-oxidative damage.