This research program targets the chemical and chemoenzymatic synthesis of sperm CD52 glycosylphosphatidylinositols (GPIs) and glycopeptides, as well as the intact antigen, and the investigation of the impacts of GPI and Nglycans on the peptide structure of CD52 using synthetic samples and NMR methods. New synthetic strategies will be used to prepare the CD52 GPI and glycopeptides in properly protected forms. Deprotection will afford the free GPI and glycopeptides, while selective coupling prior to deprotection will afford the intact CD52. Solution structures of CD52 glycopeptides and antigens will be analyzed by NMR spectroscopy.
Professor Zhongwu Guo, of the Department of Chemistry at Case Western Reserve University, is supported by the Organic and Macromolecular Chemistry Program for his synthetic and structural studies of sperm CD52 glycopeptides. Sperm CD52, which belongs to a special group of sugar-containing proteins that are anchored to cell membranes through molecules known as glycosylphosphatidylinositols (GPIs), plays a critical role in the human reproduction process. However, the difficulty to obtain pure forms of sperm CD52 has severely hindered further detailed studies about this important compound. This project aims at solving the problem through total synthesis and will advance chemistry by developing new synthetic methods for GPIs, glycopeptides and GPI-anchored glycopeptides. The efficient synthesis of these compounds, including specially labeled ones, will facilitate structural and biological studies. The structural analysis of synthetic CD52 glycopeptides and antigens will expand the knowledge regarding the impacts of GPIs on peptide structures, which combined with biological studies will help understand the structure-activity relationships of sperm CD52. The results may ultimately facilitate the understanding of the human reproduction process.
