Construction of Insulin 18-mer Nanoassemblies Driven by Coordination to Iron(II) and Zinc(II) Ions at Distinct Sites

• Published in: Angewandte Chemie 2016-02, Vol.128 (7), p.2424-2427
• Main Authors: Munch, Henrik K., Nygaard, Jesper, Christensen, Niels Johan, Engelbrekt, Christian, Østergaard, Mads, Porsgaard, Trine, Hoeg-Jensen, Thomas, Zhang, Jingdong, Arleth, Lise, Thulstrup, Peter W., Jensen, Knud J.
• Format: Article
• Language: eng ; ger
• Subjects: Affinity; Attachment; Binding sites; Chemical synthesis; Chemistry; Construction; Formations; Hexamers; Insulin; Ions; Iron; Kleinwinkel-Röntgenstreuung; Ligands; Materials selection; Metal ions; Metals; Nanostructure; Nanostrukturen; Nanotechnology; Oligomers; Proteins; Rastersondenverfahren; Scattering; Selbstorganisation; Self assembly; Small angle X ray scattering; Trimers; X-ray scattering; Zinc
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.201509088

Controlled self‐assembly (SA) of proteins offers the possibility to tune their properties or to create new materials. Herein, we present the synthesis of a modified human insulin (HI) with two distinct metal‐ion binding sites, one native, the other abiotic, enabling hierarchical SA through coordination with two different metal ions. Selective attachment of an abiotic 2,2′‐bipyridine (bipy) ligand to HI, yielding HI–bipy, enabled ZnII‐binding hexamers to SA into trimers of hexamers, [[HI–bipy]6]3, driven by octahedral coordination to a FeII ion. The structures were studied in solution by small‐angle X‐ray scattering and on surfaces with AFM. The abiotic metal ligand had a higher affinity for FeII than ZnII ions, enabling control of the hexamer formation with ZnII and the formation of trimers of hexamers with FeII ions. This precise control of protein SA to give oligomers of oligomers provides nanoscale structures with potential applications in nanomedicine. Durchstrukturiert: Metallionen vermitteln die Bildung von definierten 18‐meren Insulin‐Nanoaggregaten aus modifizierten Humaninsulin‐Molekülen (schwarze Dreiecke im Schema). Die Bindung an ZnII (grüne Kreise) über einen abiotischen 2,2′‐Bipyridin‐Ligand (rote Ellipse) führt zu Hexameren, die wiederum durch Koordination an ein FeII‐Ion (blauer Kreis) trimerisieren.