Chemo‐ and Regioselective Ethynylation of Tryptophan‐Containing Peptides and Proteins. Issue 5 (22nd December 2015)

• Record Type: Journal Article
• Authors: Hansen, Morten Borre; Hubálek, František; Skrydstrup, Troels; Hoeg‐Jensen, Thomas
• Is Part Of: Chemistry. Volume 22:Issue 5(2016)
• Page Start: 1572
• Page End: 1576
• Publication Date: 2015-12-22
• Subjects: alkynylation -- C−H activation -- chemoselectivity -- gold -- peptides; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201504462
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Ethynylation of various tryptophan‐containing peptides and a single model protein was achieved using Waser's reagent, 1‐[(triisopropylsilyl)ethynyl]‐1, 2‐benziodoxol‐3(1 H )‐one (TIPS‐EBX), under gold(I) catalysis. It was demonstrated by NMR that the ethynylation occured selectively at the C2‐position of the indole ring of tryptophan. Further, MS/MS showed that the tryptophan residues could be modified selectively with ethynyl functionalities even when the tryptophan was present as a part of the protein. Finally, the terminal alkyne was used to label a model peptide with a fluorophore by means of copper‐catalyzed click chemistry. Abstract : Alkynes on a gold Tr(i)p ! Various peptides and one model protein were functionalized with ethynyl moieties at their tryptophan residues using Waser's reagent, TIPS‐EBX, under gold(I) catalysis (see scheme; TIPS=triisopropylsilyl). The reaction proceeded in a regio‐ and chemoselective manner leading to C2 substitution at the tryptophan residues only. Subsequently, the terminal alkyne was used to label one of the model peptides with a fluorophore by means of copper‐catalyzed click chemistry.