Shinichi Sato

A photocatalyst ([Ru(bpy)3]2+) bound to a protein ligand was essential for the title method. Local single-electron transfer from the catalyst resulted in the formation of tyrosyl radicals. N′-Acetyl-N,N-dimethyl-1,4-phenylenediamine was used as the tyrosyl radical trapping agent and used in a radical addition to afford selective modification of the target protein. Techniques for the visualization of target proteins in living systems are highly important to investigate the function, dynamics, loc

While electrophilic reagents for histidine labeling have been developed, we report an umpolung strategy for histidine functionalization. A nucleophilic small molecule, 1-methyl-4-arylurazole, selectively labeled histidine under singlet oxygen (¹O₂) generation conditions. Rapid histidine labeling can be applied for instant protein labeling. Utilizing the short diffusion distance of ¹O₂ and a technique to localize the ¹O₂ generator,

Targeting less abundant amino acid residues on the protein surface may realize site-selective protein modification of natural proteins. The relative hydrophobicity of tyrosine combined with the π-π stacking tendency of the aromatic rings results in generally low accessibility. In this study, site-selective protein modification was achieved by targeting surface-exposed tyrosine residues without using a genetic encoding system. Tyrosine residues were modified with N-methylated luminol derivative u

Tyrosine-specific chemical modification was achieved using in situ hemin-activated luminol derivatives. Tyrosine residues in peptide and protein were modified effectively with N-methylated luminol derivatives under oxidative conditions in the presence of hemin and H2O2. Both single and double modifications of the tyrosine residue occurred in the reaction of angiotensin II with N-methylated luminol derivative 9. Tyrosine-specific chemical modification of the model protein bovine serum albumin (BS

We designed and synthesised peptides conjugated with proline linkers and ruthenium photocatalysts. These peptides were used as substrates to evaluate the photocatalyst-proximity dependences of candidates for tyrosine labelling reagents. The 1-methyl-4-aryl-urazole (MAUra) structure was found to be a novel tyrosyl radical trapping agent to label tyrosine residues effectively under the conditions where the ruthenium photocatalyst and tyrosine were in close proximity. Using a ruthenium photocatalys

Ligand-directed Ru(bpy)3 photocatalysts induce chromophore-assisted light inactivation (CALI) of target proteins under visible light irradiation in vitro and within cells. Here, histidine, methionine, and tryptophan residues were oxidized by the singlet oxygen ((1)O2) generated by Ru(bpy)3 with light. The addition of a tyrosyl radical trapper (TRT), such as N'-acyl-N,N-dimethyl phenylenediamine, inhibited peptide/protein oxidation and induced labeling on the tyrosine residue. This mechanistic st

The efficiency of protein chemical modification on tyrosine residues with N-methylluminol derivatives was drastically improved by using horseradish peroxidase (HRP). In the previous method, based on the use of hemin and H₂ O₂ , oxidative side reactions such as cysteine oxidation were problematic for functionalization of proteins selectively on tyrosine residues. Oxidative activation of N-methylluminol derivatives with a minimum amount of H₂ O₂ prevente

Chemical labeling of proteins with synthetic low-molecular-weight probes is an important technique in chemical biology. To achieve this, it is necessary to use chemical reactions that proceed rapidly under physiological conditions (i.e., aqueous solvent, pH, low concentration, and low temperature) so that protein denaturation does not occur. The radical reaction satisfies such demands of protein labeling, and protein labeling using the biomimetic radical reaction has recently attracted attention

Ein Photokatalysator, [Ru(bpy)3]2+, der an einen Proteinliganden gebunden ist, war entscheidend für die Entwicklung der Titelmethode. Ein lokaler Einelektronentransfer vom Katalysator führte zur Bildung von Tyrosylradikalen, und N′-Acetyl-N,N-dimethyl-1,4-phenylendiamin wurde als Tyrosylradikalfänger genutzt. Die Radikaladdition ermöglichte die selektive Modifizierung des Zielproteins. As a service to our authors and readers, this journal provides supporting information supplied by the authors.

A laccase-catalysed tyrosine click reaction proceeded between the tyrosine modification reagent N-methyl luminol and tyrosine residues in peptides/proteins. Laccase-catalysed tyrosine-specific modification under mild reaction conditions (shaking at 37 °C) was more efficient than previously reported tyrosine click reactions using hemin, horseradish peroxidase (HRP) or electrochemistry.