Elektronentransfer in Peptiden: Bildung von Silbernanopartikeln

Kracht, Sonja; Messerer, Matthias; Lang, Matthieu; Eckhardt, Sonja; Lauz, Miriam; Grobéty, Bernard; Fromm, Katharina M.; Giese, Bernd

doi:10.1002/ange.201410618

Cited by 10 publications

(4 citation statements)

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“…Such peptides can be designed to conform to specific secondary structures, such as helices and β-strands, to allow the dynamics and kinetics of electron transfer to be studied in a more controlled environment. 3,4 In addition, they can be specifically functionalized along their backbone to enable precision-branching, analogous to three-dimensional molecular circuitry. 5 While molecular electronics provides an opportunity to begin to redefine integrated circuit technologies, 6 one must first understand and subsequently be able to predict and control the associated charge transfer dynamics and mechanisms before this vision can be realized.…”

Section: Introductionmentioning

confidence: 99%

Peptides as Bio-Inspired Electronic Materials: An Electrochemical and First-Principles Perspective

Horsley

2018

Acc. Chem. Res.

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Molecular electronics is at the forefront of interdisciplinary research, offering a significant extension of the capabilities of conventional silicon-based technology as well as providing a possible stand-alone alternative. Bio-inspired molecular electronics is a particularly intriguing paradigm, as charge transfer in proteins/peptides, for example, plays a critical role in the energy storage and conversion processes for all living organisms. However, the structure and conformation of even the simplest protein is extremely complex, and therefore, synthetic model peptides comprising well-defined geometry and predetermined functionality are ideal platforms to mimic nature for the elucidation of fundamental biological processes while also enhancing the design and development of single-peptide electronic components. In this Account, we first present intramolecular electron transfer within two synthetic peptides, one with a well-defined helical conformation and the other with a random geometry, using electrochemical techniques and computational simulations. This study reveals two definitive electron transfer pathways (mechanisms), the natures of which are dependent on secondary structure. Following on from this, electron transfer within a series of well-defined helical peptides, constrained by either Huisgen cycloaddition, ring-closing metathesis, or a lactam bridge, was determined. The electrochemical results indicate that each constrained peptide, in contrast to a linear counterpart, exhibits a remarkable shift of the formal potential to the positive (>460 mV) and a significant reduction of the electron transfer rate constant (up to 15-fold), which represent two distinct electronic "on/off" states. High-level calculations demonstrate that the additional backbone rigidity provided by the side-bridge constraints leads to an increased reorganization energy barrier, which impedes the vibrational fluctuations necessary for efficient intramolecular electron transfer through the peptide backbone. Further calculations reveal a clear mechanistic transition from hopping to superexchange (tunneling) stemming from side-bridge gating. We then extended our research to fine-tuning of the electronic properties of peptides through both structural and chemical manipulation, to reveal an interplay between electron-rich side chains and backbone rigidity on electron transfer. Further to this, we explored the possibility that the side-bridge constraints present in our synthetic peptides provide an additional electronic transport pathway, which led to the discovery of two distinct forms of quantum interferometer. The effects of destructive quantum interference appear essentially through both the backbone and an alternative tunneling pathway provided by the side bridge in the constrained β-strand peptide, as evidenced by a correlation between electrochemical measurements and conductance simulations for both linear and constrained β-strand peptides. In contrast, an interplay between quantum interference effects and vibrational fluctuations ...

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Section: Introductionmentioning

confidence: 99%

Peptides as Bio-Inspired Electronic Materials: An Electrochemical and First-Principles Perspective

Horsley

2018

Acc. Chem. Res.

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“…To verify this hypothesis, follow‐up studies used tetrapeptides His‐X‐Y‐Tyr (1) and His‐X‐Y‐Phe (2), replacing tyrosine with phenylalanine, and where X and Y are Pro and Aib, respectively, were synthesized (Figure 4b and ref. [122]). NMR‐titrations showed that the silver ion binds in a first step to histidine as confirmed by single‐crystal X‐ray diffraction.…”

Section: Mechanisms Of Microbial Synthesis Of Nanoparticlesmentioning

confidence: 99%

“…Then, the initially formed AgNPs, based on chemical reduction, serve as nucleation points for the further and rapid addition of atoms from the light‐induced reduction. [ 122 ] Thus, a synergic mechanism combining the chemical and the light‐induced reduction of silver ions should be considered, taking into consideration the experimental conditions. Indeed, due to the variation in the composition of the growth media and buffer solutions in which the experiments are being carried out, reducing molecules may be present.…”

Section: Mechanisms Of Microbial Synthesis Of Nanoparticlesmentioning

confidence: 99%

“…For example, in presence of the model tetrapeptide 1, the formation of AgCl crystals with a random size distribution of particles between ≈20 and 400 nm before irradiation is observed. [ 122 ] After 30 s of irradiation, the size distribution narrowed to ≈100 ± 50 nm and first AgNPs were detected ( Figure ). After 4 min of irradiation, two types of NPs were observed: AgNPs of around 15 nm and AgCl NPs of ≈100 nm, and the TEM showed the formation of a nanocomposite of the two compounds.…”

Section: Mechanisms Of Microbial Synthesis Of Nanoparticlesmentioning

confidence: 99%

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Metal Nanoparticle–Microbe Interactions: Synthesis and Antimicrobial Effects

Khan

Fromm

Rizvi

et al. 2020

Part & Part Syst Charact

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metal solution, reduction of the metal ions leads to the generation of metal atom clustering generating nanosized particles. A characteristic of biosynthetic NPs is their high stability as the organisms provide their own biomolecular capping agent(s). [1] While plant-based production of NPs is now considered a scientific curiosity rather than a promising biotechnology, [2] bacteriamediated NP biosynthesis offers better chances, in light of the poorly characterized microbial diversity and the complex chemistry of enzymes in metal-reducing bacteria. Two recent works focused on directed biofabrication of CdSe-nanoparticles through regulating extracellular electron transfer [3] and the biosynthesis of highly active copper NPs (CuNP) by Shewanella oneidensis. [4] However, the description of molecular mechanism(s) involved in the biosynthesis of NPs has received little attention, which is the focus of this review.The CFCF or culture supernatants (CS) of bacteria mediate the synthesis of AgNPs [5] as presented in this section. The CFCF from the family Enterobacteriaceae reduce silver ions to AgNPs ( Table 1). CFCF of Klebsiella pneumoniae, Escherichia coli, and Metal nanoparticles (NPs), chalcogenides, and carbon quantum dots can be easily synthesized from whole microorganisms (fungi and bacteria) and cell-free sterile filtered spent medium. The particle size distribution and the biosynthesis time can be somewhat controlled through the biomass/metal solution ratio. The biosynthetic mechanism can be explained through the ionreduction theory and UV photoconversion theory. Formation of biosynthetic NPs is part of the detoxification strategy employed by microorganisms, either in planktonic or biofilm form, to reduce the chemical toxicity of metal ions. In fact, most reports on NP biosynthesis show extracellular metal ion reduction. This is important for environmental and industrial applications, particularly in biofilms, as it allows in principle high biosynthetic rates. The antimicrobial and antifungal effect on biosynthetic NPs can be explained in terms of reactive oxygen species and can be enhanced by the capping agents attached to the NP during the biosynthesis process. Industrial applications of NP biosynthesis are still lagging, due to the difficulty of controlling NP size and low titer. Further, the environmental assessment of biosynthetic NPs has not yet been carried out. It is expected that further advancements in biosynthetic NP research will lead to applications, particularly in environmental biotechnology.

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Kontrollierte lichtvermittelte Synthese von Gold‐Nanopartikeln über Norrish‐Typ‐I‐Reaktion in photoaktiven Polymeren

et al. 2015

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Gold‐Nanopartikel (AuNPs) erfahren zurzeit aufgrund ihrer interessanten physikochemischen Eigenschaften große wissenschaftliche Beachtung. Wir stellen hier eine einfache und kontrollierte lichtvermittelte Synthese von Gold‐Nanopartikeln über Norrish‐Typ‐I‐Reaktion in photoaktiven Polymeren vor. Diese funktionell konzipierten Polymere agieren sowohl als Reagentien zur photochemischen Reduktion von Goldionen als auch zur Stabilisierung der in situ hergestellten AuNPs. Durch geschickte Variation der Länge und der Zusammensetzung der photoaktiven Polymere kann die Größe der Gold‐Nanopartikel in einem Bereich zwischen 1.5 nm und 9.6 nm gezielt eingestellt werden.

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Elektronentransfer in Peptiden: Bildung von Silbernanopartikeln

Cited by 10 publications

References 48 publications

Peptides as Bio-Inspired Electronic Materials: An Electrochemical and First-Principles Perspective

Peptides as Bio-Inspired Electronic Materials: An Electrochemical and First-Principles Perspective

Metal Nanoparticle–Microbe Interactions: Synthesis and Antimicrobial Effects

Kontrollierte lichtvermittelte Synthese von Gold‐Nanopartikeln über Norrish‐Typ‐I‐Reaktion in photoaktiven Polymeren

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