Glycosylation of an alpha-helical hairpin peptide: A model system for studying the possible role of glycosylation in signal transduction

• Main Authors: Fu-Cheng Liang, 梁甫呈
• Other Authors: Sunney I. Chan
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/50152016243294978089

碩士 === 國立臺灣大學 === 化學研究所 === 90 === The dynamic glycosylation of serine or threonine residues on nuclear and cytosolic proteins by an O-linked beta-N-acetylglucosamine (O-GlcNAc) is abundant in all multicellular eukaryotes. Accumulating evidence implicates this kind of glycosylation (also named O-GlcNAcylation) in the regulation of numerous cellular processes, including nuclear import, protein translation, gene transcription and cytoskeletal formation. Here we synthesized an alpha-helical hairpin peptide (alpha-helix/turn/alpha-helix) and used this peptide as a model system to explore how the glycosylation affects the properties of the peptide. One beta-N-acetylglucosamine was added to the hydroxyl group of the threonine residue in the turn region. The properties of the glycosylated peptide in the aqueous solution and in the lipid bilayer were compared with those of the wild-type peptide. The analysis of 2-D NMR spectra indicates that O-GlcNAcylation substantially affects the local conformation of the peptide in aqueous solution. We also utilized attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and 15N labeled solid state NMR technique to examine if the glycosylation can transfer signals across the membrane by altering the helix orientation.