Issue 18, 2022

Triazolinedione protein modification: from an overlooked off-target effect to a tryptophan-based bioconjugation strategy

Abstract

Labelling of tyrosine residues in peptides and proteins has been reported to selectively occur via a ‘tyrosine-click’ reaction with triazolinedione reagents (TAD). However, we here demonstrate that TAD reagents are actually not selective for tyrosine and that tryptophan residues are in fact also labelled with these reagents. This off-target labelling remained under the radar as it is challenging to detect these physiologically stable but thermally labile modifications with the commonly used HCD and CID MS/MS techniques. We show that selectivity of tryptophan over tyrosine can be achieved by lowering the pH of the aqueous buffer to effect selective Trp-labelling. Given the low relative abundance of tryptophan compared to tyrosine in natural proteins, this results in a new site-selective bioconjugation method that does not rely on enzymes nor unnatural amino acids and is demonstrated for peptides and recombinant proteins.

Graphical abstract: Triazolinedione protein modification: from an overlooked off-target effect to a tryptophan-based bioconjugation strategy

Supplementary files

Article information

Article type
Edge Article
Submitted
12 dec 2021
Accepted
14 mrt 2022
First published
15 mrt 2022
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2022,13, 5390-5397

Triazolinedione protein modification: from an overlooked off-target effect to a tryptophan-based bioconjugation strategy

K. W. Decoene, K. Unal, A. Staes, O. Zwaenepoel, J. Gettemans, K. Gevaert, J. M. Winne and A. Madder, Chem. Sci., 2022, 13, 5390 DOI: 10.1039/D1SC06942J

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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