121363-58-4Relevant articles and documents
Investigating cellular metabolism of synthetic azidosugars with the Staudinger ligation
Saxon, Eliana,Luchansky, Sarah J.,Hang, Howard C.,Yu, Chong,Lee, Sandy C.,Bertozzi, Carolyn R.
, p. 14893 - 14902 (2002)
The structure of sialic acid on living cells can be modulated by metabolism of unnatural biosynthetic precursors. Here we investigate the conversion of a panel of azide-functionalized mannosamine and glucosamine derivatives into cell-surface sialosides. A key tool in this study is the Staudinger ligation, a highly selective reaction between modified triarylphosphines and azides that produces an amide-linked product. A preliminary study of the mechanism of this reaction, and refined conditions for its in vivo execution, are reported. The reaction provided a means to label the glycoconjugate-bound azidosugars with biochemical probes. Finally, we demonstrate that the cell-surface Staudinger ligation is compatible with hydrazone formation from metabolically introduced ketones. These two strategies provide a means to selectively modify cell-surface glycans with exogenous probes.
Changes in metabolic chemical reporter structure yield a selective probe of O -GlcNAc modification
Chuh, Kelly N.,Zaro, Balyn W.,Piller, Friedrich,Piller, Véronique,Pratt, Matthew R.
supporting information, p. 12283 - 12295 (2014/11/07)
Metabolic chemical reporters (MCRs) of glycosylation are analogues of monosaccharides that contain bioorthogonal functionalities and enable the direct visualization and identification of glycoproteins from living cells. Each MCR was initially thought to report on specific types of glycosylation. We and others have demonstrated that several MCRs are metabolically transformed and enter multiple glycosylation pathways. Therefore, the development of selective MCRs remains a key unmet goal. We demonstrate here that 6-azido-6-deoxy-N- acetyl-glucosamine (6AzGlcNAc) is a specific MCR for O-GlcNAcylated proteins. Biochemical analysis and comparative proteomics with 6AzGlcNAc, N-azidoacetyl-glucosamine (GlcNAz), and N-azidoacetyl-galactosamine (GalNAz) revealed that 6AzGlcNAc exclusively labels intracellular proteins, while GlcNAz and GalNAz are incorporated into a combination of intracellular and extracellular/lumenal glycoproteins. Notably, 6AzGlcNAc cannot be biosynthetically transformed into the corresponding UDP sugar-donor by the canonical salvage-pathway that requires phosphorylation at the 6-hydroxyl. In vitro experiments showed that 6AzGlcNAc can bypass this roadblock through direct phosphorylation of its 1-hydroxyl by the enzyme phosphoacetylglucosamine mutase (AGM1). Taken together, 6AzGlcNAc enables the specific analysis of O-GlcNAcylated proteins, and these results suggest that specific MCRs for other types of glycosylation can be developed. Additionally, our data demonstrate that cells are equipped with a somewhat unappreciated metabolic flexibility with important implications for the biosynthesis of natural and unnatural carbohydrates.
Mechanism of multivalent carbohydrate-protein interactions studied by EPR spectroscopy
Braun, Patrick,N?gele, Bettina,Wittmann, Valentin,Drescher, Malte
supporting information; scheme or table, p. 8428 - 8431 (2011/10/31)
From a distance: Distance measurements in the nanometer range by means of spin-label electron paramagnetic resonance provide structural evidence for multivalent protein-ligand interactions in solution (see picture; protein subunits: blue/green, ligand: bl
