Decoding the Sulfation Code: Selectively Sulfated Glycomacromolecules as Tools to Investigate Viral Protein-Carbohydrate Recognition

PROJECT SUMMARY Heparan sulfate proteoglycans (HSPGs) are a complex group of glycosylaminoglycans (GAGs) that are involved in several important biological processes including embryonic development, inflammation, angiogenesis, neurodegeneration, cardiovascular disorders, cancer. HSPGs have also been shown to play various roles in the infection of a number of viruses including HSV-1 and HSV-2, Human Papilloma Viruses (HPV), Human Immunodeficiency Virus (HIV), Dengue viruses (DENV), Hepatitis B Viruses (HBV), Hepatitis C Virus (HCV), Hepatitis E Virus, (HEV), Merkel Cell Polyomavirus (MCPyV), Rabies Virus (RABV), Respiratory Syncytial Virus (RSV), coronaviruses such as SARS-CoV-2 and HCoV-NL63, and Human Cytomegalovirus (HCMV). The important role of HSPGs in the viral life cycle has prompted numerous investigations into the use of HS and structural analogues of HS as potential compounds to study HSPG-viral engagement often with the goal of developing a better understanding of sulfation code. In most cases, these structures have been derived from natural sources or prepared synthetically. However, there remain several limitations to their use. First, structures generated from native HSPGs are often heterogeneous, making it difficult to perform the types of structure- function analyses that might unlock the sulfation code. Synthetic and semisynthetic glycans with precise sulfation patterns can be used to overcome this limitation, but they are difficult to prepare. Synthetic sulfated glycomacromolecules (oligomers and polymers) designed to serve as tools to mimic heparan sulfate have helped to overcome some of these limitations, particularly in their relative ease of synthesis. However, it is often difficult to replicate the unique sulfation patterning observed in HS. To address these shortcomings, our team will develop a library of glycomacromolecules (oligomers and polymers) bearing selectively sulfated sugars to more rapidly explore how factors such as carbohydrate content, sulfation patterns, sulfation density, and presentation (flexibility/rigidity) influence viral recognition. We also propose performing an initial assessment of the ability of our library of compounds to engage viral surface proteins of three model respiratory viruses: HPV16, SARS- CoV-2 and IAV. Finally, this proposal will provide exceptional research experiences for multiple undergraduates, fostering the training of the next generation of glycoscientists.