title: Perfluoroalkyl chains direct novel self-assembly of insulin.
abstract: The self-assembly of biopharmaceutical peptides into multimeric, nanoscale objects, as well as their disassembly to monomers, is central for their mode of action. Here, we describe a bioorthogonal strategy, using a non-native recognition principle, for control of protein self-assembly based on intermolecular fluorous interactions and demonstrate it for the small protein insulin. Perfluorinated alkyl chains of varying length were attached to desB30 human insulin by acylation of the ε-amine of the side-chain of LysB29. The insulin analogues were formulated with Zn(II) and phenol to form hexamers. The self-segregation of fluorous groups directed the insulin hexamers to self-assemble. The structures of the systems were investigated by circular dichroism (CD) spectroscopy and synchrotron small-angle X-ray scattering. Also, the binding affinity to the insulin receptor was measured. Interestingly, varying the length of the perfluoroalkyl chain provided three different scenarios for self-assembly; the short chains hardly affected the native hexameric structure, the medium-length chains induced fractal-like structures with the insulin hexamer as the fundamental building block, while the longest chains lead to the formation of structures with local cylindrical geometry. This hierarchical self-assembly system, which combines Zn(II) mediated hexamer formation with fluorous interactions, is a promising tool to control the formation of high molecular weight complexes of insulin and potentially other proteins.
authors: IGM, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark.
authors: Leila
authors: L
authors: Malik
authors: Jesper
authors: J
authors: Nygaard
authors: Rasmus
authors: R
authors: Hoiberg-Nielsen
authors: Lise
authors: L
authors: Arleth
authors: Thomas
authors: T
authors: Hoeg-Jensen
authors: Knud J
authors: KJ
authors: Jensen
mesh_terms: D002942:Circular Dichroism; D006801:Humans; D007328:Insulin / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D012542:Scattering, Radiation
chemical_list: D007328:Insulin