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- Malik, Leila, et al.
(författare)
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Self-assembly of designed coiled coil peptides studied by small-angle X-ray scattering and analytical ultracentrifugation
- 2013
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Ingår i: Journal of Peptide Science. - : Wiley. - 1099-1387 .- 1075-2617. ; 19:5, s. 283-292
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Tidskriftsartikel (refereegranskat)abstract
- alpha-Helical coiled coil structures, which are noncovalently associated heptad repeat peptide sequences, are ubiquitous in nature. Similar amphipathic repeat sequences have also been found in helix-containing proteins and have played a central role in de novo design of proteins. In addition, they are promising tools for the construction of nanomaterials. Small-angle X-ray scattering (SAXS) has emerged as a new biophysical technique for elucidation of protein topology. Here, we describe a systematic study of the self-assembly of a small ensemble of coiled coil sequences using SAXS and analytical ultracentrifugation (AUC), which was correlated with molecular dynamics simulations. Our results show that even minor sequence changes have an effect on the folding topology and the self-assembly and that these differences can be observed by a combination of AUC, SAXS, and circular dichroism spectroscopy. A small difference in these methods was observed, as SAXS for one peptide and revealed the presence of a population of longer aggregates, which was not observed by AUC. Copyright (c) 2013 European Peptide Society and John Wiley & Sons, Ltd.
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| 2. |
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| 3. |
- Munch, Henrik K, et al.
(författare)
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Construction of Insulin 18-mer Nanoassemblies Driven by Coordination to Iron(II) and Zinc(II) Ions at Distinct Sites.
- 2016
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Ingår i: Angewandte Chemie (International edition). - : Wiley. - 1521-3773. ; 55:7, s. 2378-2381
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Tidskriftsartikel (refereegranskat)abstract
- 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 Zn(II) -binding hexamers to SA into trimers of hexamers, [[HI-bipy]6 ]3 , driven by octahedral coordination to a Fe(II) 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 Fe(II) than Zn(II) ions, enabling control of the hexamer formation with Zn(II) and the formation of trimers of hexamers with Fe(II) ions. This precise control of protein SA to give oligomers of oligomers provides nanoscale structures with potential applications in nanomedicine.
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| 4. |
- Nygaard, Jesper, et al.
(författare)
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Metal Ion Controlled Self-Assembly of a Chemically Reengineered Protein Drug Studied by Small-Angle X-ray Scattering
- 2012
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 28:33, s. 12159-12170
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Tidskriftsartikel (refereegranskat)abstract
- Precise control of the oligomeric state of proteins is of central importance for biological function and for the properties of biopharmaceutical drugs. Here, the self-assembly of 2,2'-bipyridine conjugated monomeric insulin analogues, induced through coordination to divalent metal ions, was studied. This protein drug system was designed to form non-native homo-oligomers through selective coordination of two divalent metal ions, Fe(II) and Zn(II), respectively. The insulin type chosen for this study is a variant designed for a reduced tendency toward native dimer formation at physiological concentrations. A small-angle X-ray scattering analysis of the bipyridine-modified insulin system confirmed an organization into a novel well-ordered structure based on insulin trimers, as induced by the addition of Fe(II). In contrast, unmodified monomeric insulin formed larger and more randomly structured assemblies upon addition of Fe(II). The addition of Zn(II), on the other hand, led to the formation of small quantities of insulin hexamers for both the bipyridine-modified and the unmodified monomeric insulin. Interestingly, the location of the bipyridine-modification significantly affects the tendency to hexamer formation as compared to the unmodified insulin. Our study shows how combining a structural study and chemical design can be used to obtain molecular understanding and control of the self-assembly of a protein drug. This knowledge may eventually be employed to develop an optimized in vivo drug release profile.
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