Light-Controlled Tyrosine Nitration of Proteins.

Tyrosine nitration of proteins is one of the most important oxidative post-translational modifications in vivo. A major obstacle for its biochemical and physiological studies is the lack of efficient and chemoselective protein tyrosine nitration reagents. Herein, we report a generalizable strategy for light-controlled protein tyrosine nitration by employing biocompatible dinitroimidazole reagents. Upon 390 nm irradiation, dinitroimidazoles efficiently convert tyrosine residues into 3-nitrotyrosine residues in peptides and proteins with fast kinetics and high chemoselectivity under neutral aqueous buffer conditions. The incorporation of 3-nitrotyrosine residues enhances the thermostability of lasso peptide natural products and endows murine tumor necrosis factor-α with strong immunogenicity to break self-tolerance. The light-controlled time resolution of this method allows the investigation of the impact of tyrosine nitration on the self-assembly behavior of α-synuclein.

Visible-light-induced self-propelled nanobots against nanoplastics.

The accumulation of plastic debris in aquatic organisms has raised serious concerns about the potential health implications of their incorporation into the food chain. However, conventional water remediation techniques are incapable of effectively removing nanoplastics (NPs) smaller than 200 nm, which can have harmful effect on animal and human health. Herein, we demonstrate the "on-the-fly" capture of NPs through their enlargement (approximately 4,100 times) using self-propelled nanobots composed of a metal-organic framework. Under visible-light irradiation, the iron hexacyanoferrate (FeHCF) nanobot exhibits fuel-free motion by electrostatically adsorbing NPs. This strategy can contribute to reducing plastic pollution in the environment, which is a significant environmental challenge. Light-induced intervalence charge transfer in the FeHCF nanobot lattice induces bipolarity on the nanobot surface, leading to the binding of negatively charged NPs. The local electron density in the lattice then triggers self-propulsion, thereby inducing agglomeration of FeHCF@NP complexes to stabilize their metastable state. The FeHCF nanobot exhibits a maximum removal capacity of 3,060 mg∙g-1 and rate constant of 0.69 min-1, which are higher than those recorded for materials reported in the literature.

Effects analysis of substituent characteristics and solvents on the photodegradation of polybrominated diphenyl ethers.

The ultraviolet spectra and electron transition information of 209 polybrominated diphenyl ethers (PBDEs) in gas were first calculated via time-dependent density functional theory using Gaussian 09 software. The main and second-order interactional effects of substituent characteristics on the photodegradation of PBDEs were then analysed using a full factorial experimental design. Solvent effects were considered to research the effect and promotion mechanism of solvent molecules on the photodegradation of PBDEs compared with that in gas. The results showed that the introduction of substituents at each position promoted excitation of PBDEs from their ground states to excited states to induce photodegradation. The different positions affected the photodegradation of PBDEs with magnitudes of para > meta > ortho. The congeners with a concentrated distribution of substituents can always be photodegraded more easily than those with separated substituents. From the viewpoint of light-induced reactions, the electron transfer reactions between molecules of PBDE* T1 and Solvent* T1 are the main driving force for the enhanced photodegradation of PBDEs in solvents compared with that in gas.