Regensburg 2019 – scientific programme

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BP: Fachverband Biologische Physik

BP 12: Poster II

BP 12.69: Poster

Tuesday, April 2, 2019, 14:00–16:00, Poster B2

Understanding the Sequence-Structure-Mechanics Relationship of Coiled Coil Dimers under Shear — Melis Goktas, Chuanfu Luo, Patricia Lopez-Garcia, Isabell Tunn, Ruby M. A. Sullan, Ana E. Bergues-Pupo, Ana Vila Verde, Reinhard Lipowsky, and •Kerstin G. Blank — Max Planck Institute of Colloids and Interfaces, Potsdam Golm Science Park, 14424 Potsdam, Germany

Coiled coils (CCs) are superhelical motifs found in many cytoskeleton and extracellular matrix proteins, suggesting that they possess mechanical function in Nature. Despite their wide abundance, surprisingly little is known about their molecular, mechanistic response to forces. With the goal of shedding light on their sequence-structure-mechanics relationship, we have characterized a series of CC heterodimers with AFM-based single molecule force spectroscopy (SMFS) and Molecular Dynamics simulations. The SMFS experiments show that CCs with a length of 3-5 heptads rupture at forces between 20-55 pN, when mechanically loaded in 'shear' geometry. Simulations show an initial rise in the force, followed by a force plateau and ultimately chain separation. During the plateau phase, the individual helixes uncoil and recoil, with recoiling being more frequent at lower pulling speeds. Modifications that stabilize the individual helices are thus expected to increase the mechanical stability of CCs. These results aid the design of CC-based molecular force sensors and material building blocks.