Nonenzymatic StereoselectiveS-Glycosylation of Polypeptides and Proteins

Abstract

Glycosylation (1-4) is an essential and powerful technique that Nature employs to regulate the properties and functions of proteins and polypeptides. Our capacity to emulate Nature's power, however, is limited by the methods available (5) to perform glycosylation on these complex biomolecules. So far, very few glycosylation reactions could operate under the conditions tolerated by biomolecules (e.g., aqueous media, mild pH, and ambient temperature), and the need to install glycosyl groups in a stereo-controlled fashion poses additional, signi cant challenges. Here we report a non-enzymatic glycosylation reaction that builds axial S-glycosidic bonds under biorelevant conditions. Our strategy exploits the exceptional functional group tolerance of radical processes, and is enabled by the design and use of allyl glycosyl sulfones as precursors to glycosyl radicals. Our method could introduce a variety of glycosyl units to the cysteine residues of polypeptides in a highly selective fashion. The power of this method is further demonstrated in the direct glycosylation of bioexpressed proteins. Computational and experimental studies provide insights into the reaction mechanism.

Umpolung strategies for the functionalization of peptides and proteins

“…This strategy provides an operationally simple procedure for stereoselective S -glycosylation under aqueous conditions and in the absence of protecting groups ( Fig. 5C ) 37 and highlights the role of umpolung strategies in the production of peptides bearing valuable post-translational modifications.…”

“…Trapping of this radical by the electrophilic Cys furnishes an S -glycosylated Cys residue ( 39 ). 37 Two iterations of this method were developed, with the first utilizing a classical pyridine sulfenyl electrophilic Cys residue ( e.g. 29 ) to generate glycosylated peptides.…”

“…5C). 37 In this approach, an allyl glycosyl sulfone (38) serves as a precursor to an unprotected, nucleophilic glycosyl radical generated under photocatalytic conditions. Trapping of this radical by the electrophilic Cys furnishes an S-glycosylated Cys residue (39).…”

Role of ABCA1 in Cardiovascular Disease

“…It is one of the most common types of PTM. To date, several different types of protein glycosylation have been reported, including N-glycosylation [ 88 , 89 ], O-glycosylation [ 90 , 91 ], C-glycosylation [ 92 , 93 ], S-glycosylation [ 94 , 95 ], and P-glycosylation [ 87 ].…”

DFT‐basierte Entdeckung von Ethynyl‐Triazolyl‐Phosphinaten als modulare Elektrophile für die chemoselektive Cystein‐Biokonjugation und Profilierung

“…[22,23] Alternativ kann eine nukleophile Aminosäure chemisch in ein Elektrophil umgewandelt werden, wie es beispielsweise bei der Umpolung von Cystein, Tyrosin und Histidin demonstriert wurde. [24][25][26][27] Eine weitere attraktive Anwendung von Elektrophilen liegt im Bereich der Chemoproteomik [28] zur zielgerichteten Anreicherung und Analyse eines spezifischen (Sub-)Proteoms. Um optimale Ergebnisse zu erzielen, sollten die Reagenzien eine hohe Markierungseffizienz, eine einheitliche Modifikation, eine ausgezeichnete Aminosäureselektivität sowie Stabilität des gebildeten Konjugats gewährleisten.…”