Chemoselective methionine bioconjugation with alkyne-bearing oxaziridine and alkyne-bearing iodonium salts was investigated as a new platform for site-selective radiolabeling of proteins and peptides with fluorine-18. Alkyne-bearing sulfimide conjugates, resulting from oxaziridine modification, underwent copper-assisted alkyne-azide cycloaddition (CuAAC) with an F-labeled PEGylated azide to afford F-labeled triazoles in excellent radiochemical yields. Diazoester sulfonium salt bioconjugates, formed from alkyne-bearing 2-diazoiodonium salts, gave low yields of F-labeled triazoles and were shown to be unstable to CuAAC conditions. Photolytic removal of the diazo group, however, afforded the trialkylsulfonium salt which smoothly underwent CuAAC with the F-labeled PEGylated azide to afford high radiochemical yields of the desired F-labeled click product. Overall, the results establish the viability of chemoselective methionine bioconjugation as a method for preparing site-selective F-labeled PET radioligands.
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http://dx.doi.org/10.1021/acs.bioconjchem.0c00256 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Institute of Pharmaceutical Sciences, University of Freiburg, Albertstr. 25, 79104, Freiburg, Germany.
Methylation and alkylation are important techniques used for the synthesis and derivatisation of small molecules and natural products. Application of S-adenosylmethionine (SAM)-dependent methyltransferases (MTs) in biotechnological hosts such as Escherichia coli lowers the environmental impact of alkylation compared to chemical synthesis and facilitates regio- and chemoselective alkyl chain transfer. Here, we address the limiting factor for SAM synthesis, methionine supply, to accelerate in vivo methylation activity.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2024
Department of Chemistry, School of Science, Westlake University, Hangzhou, 310030, Zhejiang Province, China.
Proteomics is a powerful method to comprehensively understand cellular posttranslational modifications (PTMs). Owing to low abundance, tryptic peptides with PTMs are usually enriched for enhanced coverage by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Affinity chromatography for phosphoproteomes by metal-oxide and pan-specific antibodies for lysine acetylome allow identification of tens of thousands of modification sites.
View Article and Find Full Text PDFOrg Biomol Chem
February 2024
Department of Chemistry, Muragachha Government College, Nadia-741154, West Bengal, India.
Selective chemical reactions at precise amino acid residues of peptides and proteins have become an exploding field of research in the last few decades. With the emerging utility of bioconjugated peptides and proteins as drug leads and therapeutic agents, the design of smart protocols to modulate and conjugate biomolecules has become necessary. During this modification, the most important concern of biochemists is to keep intact the structural integrity of the biomolecules.
View Article and Find Full Text PDFMar Drugs
June 2023
School of Chemistry, Monash University, Clayton, VIC 3800, Australia.
ACS Chem Biol
October 2023
Institute of Organic Chemistry and Center for Molecular Biosciences, University of Innsbruck, Innrain 80-82, 6020 Innsbruck, Austria.
Hydrolysis-resistant RNA-peptide conjugates that mimic peptidyl-tRNAs are frequently needed for structural and functional studies of protein synthesis in the ribosome. Such conjugates are accessible by chemical solid-phase synthesis, allowing for the utmost flexibility of both the peptide and the RNA sequence. Commonly used protection group strategies, however, have severe limitations with respect to generating the characteristic -formylmethionyl terminus because the formyl group of the conjugate synthesized at the solid support is easily cleaved during the final basic deprotection/release step.
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