Department of Chemistry, Graduate School of Science, Osaka University , 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
ERATO Ito glycotrilogy project, Japan Science and Technology Agency (JST) , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
J Am Chem Soc. 2017 Aug 23;139(33):11421-11426. doi: 10.1021/jacs.7b03277. Epub 2017 Aug 10.
UDP-glucose:glycoprotein glucosyltransferase (UGGT) distinguishes glycoproteins in non-native conformations from those in native conformations and glucosylates from only non-native glycoproteins. To analyze how UGGT recognizes non-native glycoproteins, we chemically synthesized site-specifically N-labeled interleukin 8 (IL-8) C-terminal (34-72) glycopeptides bearing a ManGlcNAc (M9) oligosaccharide. Chemical shift perturbation mapping NMR experiments suggested that Phe65 of the glycopeptide specifically interacts with UGGT. To analyze this interaction, we constructed a glycopeptide library by varying Phe65 with 10 other natural amino acids, via parallel native chemical ligation between a glycopeptide-α-thioester and a peptide library consisting of 11 peptides. UGGT assay against the glycopeptide library revealed that, although less hydrophobic glycopeptides could be used as substrates for UGGT, hydrophobic glycopeptides are preferred.
UDP-葡萄糖：糖蛋白葡萄糖基转移酶（UGGT）能够区分非天然构象和天然构象的糖蛋白，并仅对非天然糖蛋白进行葡萄糖基化。为了分析 UGGT 如何识别非天然糖蛋白，我们通过化学合成方法在具有 ManGlcNAc（M9）寡糖的白细胞介素 8（IL-8）C 末端（34-72）糖肽的特定位置进行了 N 标记。化学位移扰动图谱 NMR 实验表明，糖肽的 Phe65 特异性地与 UGGT 相互作用。为了分析这种相互作用，我们通过在糖肽-α-硫酯和由 11 个肽组成的肽库之间进行平行的天然化学连接，构建了一个糖肽文库，通过改变糖肽中的 Phe65 来构建文库。针对糖肽文库的 UGGT 测定表明，尽管疏水性糖肽可以用作 UGGT 的底物，但疏水性糖肽更受欢迎。
