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Modulating Protein-Protein Interactions with Visible-Light Responsive Peptide Backbone Photoswitches
摘要： Life relies on a myriad of carefully orchestrated processes, in which proteins and their direct interplay ultimately determine cellular function and disease. Modulation of these complex cross-talks has recently attracted attention, even as a novel therapeutic strategy. Here, we describe the synthesis and characterization of two visible-light responsive peptide backbone photoswitches based on azobenzene derivatives to exert optical control over protein-protein interactions (PPI). Our novel peptidomimetics undergo fast isomerization and reversibility with low photochemical fatigue under alternatively blue/green-light irradiation cycles. Both bind in the nanomolar rage to the protein of interest. Importantly, our best peptidomimetic displays a clear difference between isomers in its protein-binding capacity and, in turn, in its potential to inhibit enzymatic activity via PPI disruption. In addition, crystal structure determination, docking and MD calculations give a molecular interpretation and open new avenues in the design and synthesis of future photoswitchable PPI modulators.
关键词： protein-protein interactions,photopharmacology,visible-light irradiation,azobenzene,photoswitches
更新于2025-11-21 11:20:42
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Nuclear Spin Singlet States in Photoactive Molecules: From Fluorescence/NMR Bimodality to a Bimolecular Spin Singlet State Switch
摘要： Nuclear spin singlet states are silent states in nuclear magnetic resonance (NMR). However, they can be probed indirectly and offer great potential for the development of contrast agents for magnetic resonance imaging (MRI). Here, we are introducing two novel concepts: Firstly, we investigate the bimodal NMR/fluorescence properties of 13C2-tetraphenylethylene. It possesses a long-lived singlet state in organic solvents, which shortens upon the addition of water. This simultaneously increases the fluorescence emission in a substantial enhancement of fluorescence. Secondly, we introduce a bimolecular singlet state switch based on 3-2H-coumarin containing an isolated proton. Upon UV-light exposure, a dimer forms leading to a coupling between two previously isolated protons. A nuclear spin singlet state can now be populated. Excitation with a wavelength of 254 nm results in partly cleavage of the molecule back into its monomer.
关键词： Photoswitches,NMR spectroscopy,Aggregation induced emission,Fluorescence,Nuclear spin singlet state
更新于2025-09-23 15:23:52
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Vacuum-enhanced optical nonlinearities with disordered molecular photoswitches
摘要： It is well known that nonlinear optical signals such as cross-phase modulation can be coherently enhanced in multilevel atomic gases under conditions of electromagnetically induced transparency, but analogous results in solids are challenging to obtain due to natural energetic disorder. We propose a solid-state cavity QED scheme to enable cross-phase modulation between two arbitrarily weak classical fields in the optical domain, using a highly disordered intracavity medium composed of organic molecular photoswitches. Even in the presence of strong energetic and orientational disorder, the unique spectral properties of organic photoswitches can be used to enhance the desired nonlinearity under conditions of vacuum-induced transparency, enabling cross-phase modulation signals that surpass the detection limit imposed by absorption losses. Possible applications of the scheme include integrated all-optical switching with low photon numbers.
关键词： organic photoswitches,cavity QED,vacuum-induced transparency,cross-phase modulation,disorder
更新于2025-09-23 15:23:52
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Photoswitchable Host-Guest Systems Incorporating Hemithioindigo and Spiropyran Units
摘要： We cover selected examples of the incorporation of hemithioindigo and spiropyran units in one of the binding partners of synthetic host-guest systems. In some of the simplest systems, isomerization of the switch simply modulates the thermodynamic stability of the two isomeric host-guest complexes. In the presence of more than two binding partners, the isomerization of the molecular switch alters the composition of the multicomponent host-guest system producing a shuttling process of one of the components between different hosts. In others, the isomerization process controls the uptake and release of some of the components from/to the bulk solution. We show that the understanding of the isomerization mechanisms of the molecular switches and the effects produced by the external stimuli are essential for the design of complex and responsive supramolecular host-guest systems. The physicochemical properties of the hemithioindigo and spiropyran molecular photoswitches are complementary, providing different avenues to their applications in solution and material science.
关键词： Spiropyrans,Hemithioindigos,Host-Guest Systems,Supramolecular Assemblies,Photoswitches
更新于2025-09-23 15:22:29
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Azobenzene-based small molecular photoswitches for protein modulation
摘要： Molecular photoswitches are a class of chemical structures that can readily isomerize between distinct geometries upon irradiation with light. Molecular photoswitches are utilized to control protein structure and function with temporal and spatial precision. In this review, we summarize the recent progress in the development of azobenzene-based molecular photoswitches and their applications in the photocontrol of protein structure and function. For clarity of discussion, we divide the known photoswitchable proteins into different categories: protein motifs, ion channels, receptors, and enzymes. Basic approaches and considerations for the structure-guided design of photoswitchable ligands are discussed. The applications and limitations of current photoswitches are also discussed.
关键词： protein modulation,molecular design,azobenzene,photocontrol,photoswitches
更新于2025-09-19 17:15:36
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Second-order nonlinear optical properties of Stenhouse photoswitches: insights from density functional theory
摘要： We report the first investigation of the second-order nonlinear optical (NLO) properties of donor–acceptor Stenhouse adducts (DASAs), an emerging class of colored photochromes that undergo photoswitching with visible light to a colorless form. By using time-dependent density functional theory, we provide insights into the relationships linking the nature of the chemical substituents to the amplitude and contrasts of the NLO response. Solvent and frequency dispersion effects are also analyzed. The calculations predict that DASAs behave as high contrast NLO switches, a finding that extends their potential applications to photo-responsive NLO materials and devices.
关键词： photoswitching,Stenhouse photoswitches,nonlinear optical properties,density functional theory,second harmonic generation
更新于2025-09-19 17:15:36
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Reconfigurable Surfaces Based on Photocontrolled Dynamic Bonds
摘要： Photocontrolled surfaces have attracted increasing interest because of their potential applications in lithography, photopatterning, biointerfaces, and microfluidics. Light provides high spatiotemporal resolution to control functions of such surfaces without getting into direct contact. However, conventional photocontrolled surfaces can only be switched between two states (on and off). The development of photocontrolled reconfigurable surfaces that can be switched among multiple states is highly desirable because these surfaces can adapt to rapid environmental changes or different applications. Herein, recent developments of photocontrolled reconfigurable surfaces are reviewed. Specially, reconfigurable surfaces based on photocontrolled reversible reactions including thiol-quinone methide, disulfide exchange, thiol-disulfide interconversion, diselenide exchange, and photosubstitution of Ru complexes are highlighted. As a perspective, other photocontrolled dynamic bonds that can be used to construct reconfigurable surfaces are summarized. Remaining challenges in this field are discussed.
关键词： reconfigurable surfaces,photoswitches,photochemistry,dynamic bonds,photoresponsive
更新于2025-09-12 10:27:22
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Entangled Azobenzene‐Containing Polymers with Photoinduced Reversible Solid‐to‐Liquid Transitions for Healable and Reprocessable Photoactuators
摘要： Photoactuators based on liquid crystal elastomers or networks are smart materials that show photoinduced motions. However, their crosslinked networks make their repair or reprocessing difficult. Here, a healable and reprocessable photoactuator is fabricated using entangled high-molecular-weight azobenzene-containing polymers (azopolymers) that are non-crosslinked. A series of linear liquid crystal azopolymers with different molecular weights are synthesized. The low-molecular-weight azopolymers (5–53 kg mol?1) cannot form freestanding photoactuators because their polymer chains lack entanglements, which makes them hard and brittle. In contrast, flexible and stretchable actuators are fabricated using high-molecular-weight azopolymers (80–100 kg mol?1) that exhibit good processability because of the polymer chain entanglements. The azopolymer photoactuators show photoinduced bending based on photoinduced trans–cis isomerization of the azopolymers on the irradiated side. The experiments show not only photoinduced phase transitions or changes in the order parameters but also photoinduced solid-to-liquid transition of the azopolymers resulting in shape changes and mechanical responses. Thus, photoinduced solid-to-liquid transition is a new mechanism for the design of photoactuators. Moreover, the azopolymer photoactuators are healable and reprocessable via solution processing or light irradiation. Healability and reprocessability prolong lifetimes of photoactuators are important for materials reusage and recycling, and represent a new strategy for the preparation of smart materials.
关键词： azobenzene,actuators,photoswitches,polymers,self-healing
更新于2025-09-12 10:27:22