The activity of a gold nanoparticle-based catalyst can be reversibly up- and down-regulated by light. Light is used to switch a small molecule between cis- and trans-isomers, which inhibits the catalytic activity of the nanoparticles to different extent. The system is functional in aqueous buffer, which paves the way for integrating the system in biological networks.
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http://dx.doi.org/10.1021/jacs.6b12932 | DOI Listing |
J Am Chem Soc
December 2024
Laboratório Associado para a Química Verde (LAQV), Rede de Química e Tecnologia (REQUIMTE), Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
The photoswitching of supramolecular host-guest complexes is the basis of numerous molecularly controlled macroscopic functions, such as sol-gel transition, photopharmacology, the active transport of ions or molecules, light-powered molecular machines, and much more. The most commonly used systems employ photoactive azobenzene guests and synthetic host molecules, which bind as the stable isomers and dissociate as the forms after exposure to UV light. We present a new, extraordinarily efficient cucurbit[7]uril (CB7)/diazocine host/guest complex with inverted stability that self-assembles under UV irradiation and dissociates in the dark.
View Article and Find Full Text PDFThe LOV2 domain is commonly harnessed as a source of light-based regulation in engineered optogenetic switches. In prior work, we used LOV2 to create a light-regulated Dihydrofolate Reductase (DHFR) enzyme and showed that structurally disperse mutations in DHFR were able to tune the allosteric response to light. However, it remained unclear how light allosterically activates DHFR, and how disperse mutations modulate the allosteric effect.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2024
Friedrich-Alexander-Universität Erlangen-Nürnberg, Department of Chemistry and Pharmacy, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany.
Diarylethenes are a well-studied and optimized class of photoswitches with a wide range of applications, including data storage, smart materials, or photocontrolled catalysis and biological processes. Most recently, aza-diarylethenes have been developed in which carbon-carbon bond connections are replaced by carbon-nitrogen connections. This structural elaboration opens up an entire new structure and property space expanding the versatility and applicability of diarylethenes.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2024
Chemistry Department, Ben-Gurion University of the Negev, Campus st. 1, Beer Sheva, 8410501, Israel.
Recent attempts to mimic enzyme catalysis using simple, short peptides have been successful in enhancing various reactions, but the on-demand, temporal or spatial regulation of such processes by external triggers remains a great challenge. Light irradiation is an ideal trigger for regulating molecular functionality, since it can be precisely manipulated in time and space, and because most reaction mediums do not react to light. We herein report the selection of a photo-switchable amphiphilic peptide catalyst from a small library of isomeric peptides, each containing an azobenzene-based light responsive group and a catalytic histidine residue.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2024
School of Chemical Sciences, University of Chinese Academy of Sciences (UCAS), 100049, Beijing, P. R. China.
We have developed a new type of nanoparticles with potent antitumor activity photoactivatable via the combination of molecular photoswitching of spiropyran (SP) and enzymatic reaction of glucose oxidase (GOx). As two key processes involved therein, Fe(III)-to-Fe(II) photoreduction in Fe(III) metal-organic frameworks (MOFs) brings about the release of free Fe/Fe while the photoswitching of SP to merocyanine (MC) unlocks the enzymatic activity of GOx that was pre-passivated by SP. The release of free Fe boosts its hydrolysis and therefore enables the acidification of microenvironment, which is further reinforced by one of the products of the GOx-mediated glucose oxidation reaction, gluconic acid (GlcA).
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