Supramolecular amplification of amyloid self-assembly by iodination
Arianna Bertolani1, Lisa Pirrie1,2, Loic Stefan1, Nikolay Houbenov3, Johannes S. Haataja3, Luca Catalano1,Giancarlo Terraneo1, Gabriele Giancane4, Ludovico Valli4, Roberto Milani2, Olli Ikkala3, Giuseppe Resnati1 & PierangeloMetrangolo1,2
1Laboratory of Nanostructured Fluorinated Materials (NFMLab), Department of Chemistry, Materials, and Chemical Engineering ‘Giulio Natta’, Politecnico di Milano, Via Mancinelli 7, Milano I-20131, Italy.
2VTT-Technical Research Centre of Finland, PO Box 1000, Espoo FI-02044, Finland.
3Department of Applied Physics, Aalto University, PO Box 15100, Espoo FI-02150, Finland.
4Dipartimento Beni Culturali, Universita' del Salento, Lecce I-73100, Italy.
Nature Communications 6, Article number:7574, doi:10.1038/ncomms8574
Received 05 March 2015; Accepted 19 May 2015; Published 30 June 2015
Amyloid supramolecular assemblies have found widespread exploitation as ordered nanomaterials in a range of applications from materials science to biotechnology. New strategies are, however, required for understanding and promoting mature fibril formation from simple monomer motifs through easy and scalable processes. Noncovalent interactions are key to forming and holding the amyloid structure together. On the other hand, the halogen bond has never been used purposefully to achieve control over amyloid self-assembly. Here we show that single atom replacement of hydrogen with iodine, a halogen-bond donor, in the human calcitonin-derived amyloidogenic fragment DFNKF results in a super-gelator peptide, which forms a strong and shape-persistent hydrogel at 30-fold lower concentration than the wild-type pentapeptide. This is remarkable for such a modest perturbation in structure. Iodination of aromatic amino acids may thus develop as a general strategy for the design of new hydrogels from unprotected peptides and without using organic solvents.
