Marchiori Marcelo Fiori, Iossi Giulia Pompolo, Bortot Leandro Oliveira, Dias-Baruffi Marcelo, Campo Vanessa Leiria
Faculty of Pharmaceutical Sciences of Ribeirão Preto - USP, Av. do Café S/N, CEP 14040-903, Ribeirão Preto, SP, Brazil.
Faculty of Pharmaceutical Sciences of Ribeirão Preto - USP, Av. do Café S/N, CEP 14040-903, Ribeirão Preto, SP, Brazil; Barão de Mauá University Centre, 423 Ramos de Azevedo Street, Jardim Paulista, CEP 14090-180, Ribeirão Preto, SP, Brazil.
Carbohydr Res. 2019 Jan 15;472:23-32. doi: 10.1016/j.carres.2018.11.004. Epub 2018 Nov 11.
α-Dystroglycan (α-DG) mucins are essential for maintenance of the structural and functional stability of the muscle fiber and, when hypoglycosylated, they are directly involved in pathological processes such as dystroglycanopathies. Thus, this work reports the synthesis of the novel 1,2,3-triazole-derived glycosyl amino acids αGlcNAc-1-O-triazol-2Manα-ThrOH (1) and Gal-β1,4-αGlcNAc-1-O-triazol-2Manα-ThrOH (2), followed by solid-phase assembly to get the corresponding glycopeptides NHAcThrVal[αGlcNAc-1-triazol-2Manα]ThrIleArgGlyOH (3) and NHAcThrVal[Gal-β1,4-αGlcNAc-1-triazol-2Manα]ThrIleArgGlyOH (4) as analogs of α-DG mucins. The glycosyl amino acids 1 (72%) and 2 (35%) were synthesized by Cu(I)-assisted 1,3-dipolar azide-alkyne cycloaddition reactions (CuAAC) between the azide-glycosyl amino acid αManN-FmocThrOBn (5) and the corresponding alkyne-functionalyzed sugars 2'-propynyl-αGlcNAc (6) and 2'-propynyl-Gal-β1,4-αGlcNAc (7), followed by hydrogenation reactions. Subsequently, glycopeptides 3 (23%) and 4 (12%) were obtained by solid phase synthesis, involving sequential couplings of Fmoc-protected amino acids or the glycosyl amino acids 1 and 2, followed by cleavage from resin, N-acetylation and O-deacetylation (NaOMe) reactions. Lastly, enzymatic galactosylation of glycopeptide 3 with bovine β-1,4-GalT showed that it was not a substrate for this enzyme, which could be better elucidated by docking simulations with β-1,4-GalT.
α- dystroglycan（α-DG）粘蛋白对于维持肌纤维的结构和功能稳定性至关重要，当糖基化不足时，它们直接参与诸如肌营养不良症等病理过程。因此，本研究报道了新型1,2,3-三唑衍生的糖基氨基酸αGlcNAc-1-O-三唑-2Manα-ThrOH（1）和Gal-β1,4-αGlcNAc-1-O-三唑-2Manα-ThrOH（2）的合成，随后通过固相组装得到相应的糖肽NHAcThrVal[αGlcNAc-1-三唑-2Manα]ThrIleArgGlyOH（3）和NHAcThrVal[Gal-β1,4-αGlcNAc-1-三唑-2Manα]ThrIleArgGlyOH（4）作为α-DG粘蛋白的类似物。糖基氨基酸1（72%）和2（35%）是通过叠氮糖基氨基酸αManN-FmocThrOBn（5）与相应的炔基官能化糖2'-丙炔基-αGlcNAc（6）和2'-丙炔基-Gal-β1,4-αGlcNAc（7）之间的铜（I）辅助1,3-偶极叠氮-炔环加成反应（CuAAC）合成的，随后进行氢化反应。随后，通过固相合成获得糖肽3（23%）和4（12%），包括Fmoc保护的氨基酸或糖基氨基酸1和2的顺序偶联，随后从树脂上裂解、N-乙酰化和O-脱乙酰化（NaOMe）反应。最后，用牛β-1,4-GalT对糖肽3进行酶促半乳糖基化反应表明它不是该酶的底物，通过与β-1,4-GalT的对接模拟可以更好地阐明这一点。
