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pH responsive peptide self-assemblies : a mechanism as old as viruses Maïté Paternostre

2UMR 8221 CNRS & CEA, CEA-Saclay, 91191 Gif sur Yvette, FRANCE


From organized biological matter to supramolecular synthetic chemistry, molecular self-assembly is the ubiquitous strategy for the construction of architectures of controlled morphology with 1–100 nm dimensions and single-nanometer precision1. In this context, we studied the self-assembly process and architecture structures formed by oligopeptides2,3. If external stimuli are powerful and typical tools that naturally control protein assemblies and functions, self-assembled nanomaterials hardly possess such responsive properties. Bio-inspired approaches could therefore open the way toward tunable self-assembled architectures. Here we study a self-assembling pH sensitive peptide that forms either highly ordered bundles of small nanotubes of 11nm diameter (pH<6.5) or large nanotubes of 50nm diameter (pH>7.5). From our structural multiscale approach, we deduce the mechanism of the peptide conformational changes driving the transition between small and large nanotubes. The sub-angström peptide crystal structure (basic pH) reveals a globular conformation stabilized through specific interactions between the lateral chains. Lowering the pH disrupts these interactions and triggers a large change to an extended β-sheet based conformation. We propose that the mechanism discovered in this study can be used to design dual nanostructures that can be switched by a pH change.

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