Regensburg 2019 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 24: Focus: Mechanoresponsive Molecules and Materials - organized by Kerstin Blank and Robert Göstl

CPP 24.4: Talk

Tuesday, April 2, 2019, 12:15–12:30, H14

How mechanical properties of coiled coils depend on the oligomerization state: comparing dimers and trimers using molecular dynamics simulations — •Ana Bergues-Pupo, Reinhard Lipowsky, Kerstin Blank, and Ana Vila Verde — Max Planck Institute of Colloids and Interfaces, Potsdam, Germany

Coiled-coils (CCs) are ubiquitous motifs in many proteins of the cytoskeleton, extracellular matrix and also in bio-engineered materials. The study of their mechanical response is crucial to understand their function and to tune their properties for specific applications. The relationship between CC sequence-structure and mechanics at the molecular level is however not fully understood. Here, we investigate different aspects of CC topology in the mechanical response under shear stress by means of molecular dynamics simulations: we compared a dimer and a trimer CC of similar sequence composition and also look at the effect of amino acids mutations and single helix stability in the mechanical response of the trimer.

The trimeric coiled coil is mechanically more stable than the dimer. The molecular mechanisms of deformation are also different: trimer exhibits irreversible helix unfolding, while unfolding/refolding assisted sliding is observed for the dimer. Interestingly, this increase on stability is almost unaffected by mutations on the hydrophobic and charged amino acids of the trimer. These interactions are known to be determinant for the thermodynamic stability. On the other hand, the mechanical strength of the trimer considerably increases if helical strength is increased such that single helix unfolding is prevented.