pH-switchable supramolecular assembly of amphiphilic peptide-dendron hybrids

Intrinsically disordered proteins (IDPs) are proteins that lack ordered three-dimensional structures. Many IDP`s undergo transitions to more ordered states upon binding to their targets or after exposure to a suitable stimulus.

Understanding synthetic IDPs based assemblies and their structural change in response to different stimuli can provide relevant insights into the principles that affect morphological changes of naturally IDP assemblies.¹

Towards this goal, we synthesized amphiphilic hybrids based on hydrophilic IDP and hydrophobic dendron.² These IDP-dendron hybrids self-assembled in aqueous medium into micellar structures. The structures were characterized using fluorescence spectroscopy, dynamic light scattering and small angle x-ray scattering. We varied the hydrophobic dendron to get better understanding on the relationship between the molecular structure of the hybrids and the assembled state morphology. Furthermore, we used different triggers such as change in the pH and increase in the ionic strength. Remarkably, huge effect was observed when we increased the acidity from 7.4 to 6, as the globular small micelles transformed into very large elongated worm-like micelles, with length of several microns.

Taking advantage of the molecular precision of these hybrids, which emerge from the monodispersity of both the peptide and the dendritic block, we were able to study their self-assembly with great resolution. This study will hopefully inspire the fabrication of future stimuli-responsive assemblies platforms.

1. DeForte, S.; Uversky, V. Order, Disorder, and Everything in Between. Molecules 2016, 21 (8), 1090.
2. Segal, M.; Avinery, R.; Buzhor, M.; Shaharabani, R.; Harnoy, A. J.; Tirosh, E.; Beck, R.; Amir, R. J. Molecular Precision and Enzymatic Degradation: From Readily to Undegradable Polymeric Micelles by Minor Structural Changes. Am. Chem. Soc. 2017,139, 803.