Aggregation-Induced Folding of a De Novo Designed Polypeptide Immobilized on Gold Nanoparticles

Aili, Daniel; Enander, Karin; Rydberg, Johan; Lundström, Ingemar; Baltzer, Lars; Liedberg, Bo

doi:10.1021/ja057056j

Cited by 76 publications

(82 citation statements)

References 13 publications

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“…First, the peptides may bind to more than one particle at a time, leading to an effect called "bridging" flocculation [21]. This effect has been used to control the interparticle spacing of aggregated gold colloid through the folding of a helix-loop-helix-forming polypeptide on the particle's surface [22]. Or, a second possibility is that the addition of positively charged peptides to negatively charged gold particles decreases electrostatic repulsion from the electrical double layer (EDL) on the particles allowing colliding particles to aggregate.…”

Section: Resultsmentioning

confidence: 99%

Tunable Assembly of Peptide-coated Gold Nanoparticles

et al. 2007

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The interaction between peptides and gold surfaces has increasingly been of interest for bionanotechnology applications. To more fully understand how to control such interactions, we have studied the optical properties of peptide-modified gold nanoparticles as a function of peptide composition, pH of the surrounding medium, and peptide concentration. We show using localized surface plasmon resonance, transmission electron microscopy, and surface-enhanced Raman scattering (SERS) that selected "gold-binding peptides" (GBPs), similar to those isolated for binding to gold films using yeast display, can bind to gold nanoparticles at a variety of pHs. Peptide modifications of nanoparticles can lead to irreversible particle aggregation when the pH of the solution is kept below the isoelectric point (pI) of the peptide. However, at pHs above the peptide's pI, particles remain stable in solution, and peptides remain bound to the particles possibly through amine coordination of gold. Additionally, we demonstrate the potential in using SERS for the direct detection of GBPs on gold-silica nanoshells, eliminating the need for indirect labeling methods.

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Section: Resultsmentioning

confidence: 99%

Tunable Assembly of Peptide-coated Gold Nanoparticles

et al. 2007

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“…44 JR2EC has a Cys residue in the loop region and the linking of two peptide monomers by a disulfide bridge (JR2EC2) results in self-assembly of micrometer long fibers at acidic pH as a result of peptide folding and a propagating homoassociation when the intra-and intermolecular charge repulsion is reduced upon protonation of Glu residues. 43 The possibility to control the peptide self-assembly process at physiological pH using Zn 2+ coordination would, however, be very attractive.…”

Section: +mentioning

confidence: 99%

Zinc-Triggered Hierarchical Self-Assembly of Fibrous Helix–Loop–Helix Peptide Superstructures for Controlled Encapsulation and Release

2016

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We demonstrate a novel route for hierarchical self-assembly of sub-micron sized peptide superstructures that respond to subtle changes in Zn 2+ concentration. The self-assembly process is triggered by a specific foldingdependent coordination of Zn 2+ by a de novo designed non-linear helix-loop-helix peptide, resulting in a propagating fiber formation and formation of spherical superstructures. The superstructures further forms larger assemblies that can be completely disassembled upon removal of Zn 2+ or degradation of the non-linear peptide.This flexible and reversible assembly strategy of the superstructures enable facile encapsulation of nanoparticles and drugs that can be released by means of different stimuli.

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“…It is also possible to design polypeptides that folds into a helical structure as a result of an interaction with a surface, [62][63] or with a complimentary peptide. 30,64 Alternatively, helices can be formed in response to external stimuli such as change of pH, 36 change of temperature, 65 or the presence of metal cations. [66][67] In this thesis de novo designed polypeptides are utilized in all papers.…”

Section: Synthetic Peptidesmentioning

confidence: 99%

“…The immobilization of the polypeptide JR2EC on gold nanoparticles creates a highly flexible hybrid nanomaterial which can be assembled by three different strategies: (i) the addition of the disulfide linked JR2KC which can heterodimerize with the tethered JR2EC bridging adjacent particles, 143 (ii) lowering the pH below 6 induces aggregation as consequence of a reduced electrostatic repulsion resulting in homodimerization of peptides tethered to particles in contact, 36 and (iii) that relies on the Zn 2+ mediated aggregation, for which the mechanism have previously described in chapter 6.4 and that has been extensively utilized in this thesis. …”

Section: Zinc(ii) Induced Aggregationmentioning

confidence: 99%

Polypeptide functionalized gold nanoparticles for bioanalytical applications

Selegård¹

2014

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Detection strategies that allow for simple, rapid, cost efficient and sensitive monitoring of proteins and their interactions with biomolecules are of great importance in drug development and diagnostics. This thesis describes the development of bioanalytical applications based on the tunable self-assembly of gold nanoparticles functionalized with a de novo designed polypeptide. Strategies for protein affinity sensing and for detection of several fundamentally important biological processes have been investigated, including Zn 2+ -mediated coordination between polypeptides and low molecular weight chelants and protease and phosphatase activity.A Zn 2+ responsive synthetic polypeptide designed to fold into a helix-loop-helix motif and dimerize into a four-helix bundle has been used to control the stability and self-assembly of gold nanoparticles. This polypeptide has a high negative net charge at neutral pH as a consequence of its many glutamic acid residues, efficiently preventing folding and dimerization due to charge repulsion. Zn 2+ coordination provides a means to trigger folding and dimerization at neutral pH. The polypeptide can be readily attached to gold nanoparticles via a cysteine residue in the loop region, retaining its folding properties and responsiveness to Zn 2+ . The polypeptide functionalized gold nanoparticles display excellent colloidal stability but aggregate reversibly after addition of millimolar concentrations of Zn 2+ . Aggregates are dense with a defined interparticle distance corresponding to the size of the four-helix bundle, resulting in a distinct red shift of the localized surface plasmon resonance band.Three completely different strategies for colorimetric biosensing have been developed, all being based on the same responsive hybrid nanomaterial. In the first strategy a synthetic receptor was co-immobilized on the gold nanoparticles together with the Zn 2+ responsive polypeptide. Protein analyte binding to the receptor could be detected as this interaction sterically prevented aggregation induced by Zn 2+ . In the second strategy the reduction in colloidal stability caused by specific proteolytic cleavage of the immobilized polypeptide was exploited to monitor the enzymatic activity. The third strategy utilized the sensitivity of the system to small variations in Zn 2+ concentration. The presence of low molecular weight chelants was found to influence the mode of aggregation, both by sequestering Zn 2+ and through the formation of ternary complexes involving the polypeptides, which prevented dimerization and thus aggregation. This approach was further developed into a generic concept for phosphatase detection exploiting the different affinity of enzyme substrates and reaction products for Zn 2+ . VThe flexibility of the different detection schemes enables detection of a large number of analytes by exploiting the tunable stability of the nanoparticles and the possibilities to effectively decouple the recognition event and the nanoparticle stability modulation. VI POPULÄRVET...

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Aggregation-Induced Folding of a De Novo Designed Polypeptide Immobilized on Gold Nanoparticles

Cited by 76 publications

References 13 publications

Tunable Assembly of Peptide-coated Gold Nanoparticles

Tunable Assembly of Peptide-coated Gold Nanoparticles

Zinc-Triggered Hierarchical Self-Assembly of Fibrous Helix–Loop–Helix Peptide Superstructures for Controlled Encapsulation and Release

Polypeptide functionalized gold nanoparticles for bioanalytical applications

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