Ethynylation of Cysteine Residues: From Peptides to Proteins in Vitro and in Living Cells. Issue 27 (11th May 2020)

• Record Type: Journal Article
• Authors: Tessier, Romain; Nandi, Raj Kumar; Dwyer, Brendan G.; Abegg, Daniel; Sornay, Charlotte; Ceballos, Javier; Erb, Stéphane; Cianférani, Sarah; Wagner, Alain; Chaubet, Guilhem; Adibekian, Alexander; Waser, Jerome
• Is Part Of: Angewandte Chemie international edition. Volume 59:Issue 27(2020)
• Page Start: 10961
• Page End: 10970
• Publication Date: 2020-05-11
• Subjects: bioconjugation -- cysteine -- ethynylation -- hypervalent iodine reagents -- proteomics; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202002626
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Current approaches to introduce terminal alkynes for bioorthogonal reactions into biomolecules still present limitations in terms of either reactivity, selectivity, or adduct stability. We present a method for the ethynylation of cysteine residues based on the use of ethynylbenziodoxolone (EBX) reagents. The acetylene group is directly introduced onto the thiol group of cysteine and can be used for copper‐catalyzed alkyne‐azide cycloaddition (CuAAC) without further processing. Labeling proceeded with reaction rates comparable to or higher than the most often used iodoacetamide on peptides or maleimide on the antibody trastuzumab, and high cysteine selectivity was observed. The reagents were also used in living cells for cysteine proteomic profiling and displayed improved coverage of the cysteinome compared to previously reported iodoacetamide or hypervalent iodine reagents. Fine‐tuning of the EBX reagents allows optimization of their reactivity and physical properties. Abstract : Right on target ! A direct ethynylation method for cysteine residues using hypervalent iodine reagents is reported. The reaction proceeds on peptides and proteins such as antibodies, and can also be used for cysteine proteomic profiling in living cells, where it provides improved coverage of the cysteinome compared to previously reported probes.