Regents Distinguished Professor and KBA Eminent Scholar, Diagnostic Medicine/Pathobiology
Kansas State University
Interaction between Rift Valley Fever Virus glycoprotein and heparan sulfate (2017-18)
Rift Valley Fever Virus (RVFV) is a devastating, mosquito-borne zoonotic disease and a palpable threat to public health. The project will provide significant structural and kinetic insights into the basis of RVFV cellular entry, necessary for the development of novel antiviral drugs and vaccines to treat and prevent RVFV infection.
Rift Valley Fever Virus (RVFV) is a mosquito-borne zoonotic pathogen that causes periodic disease outbreaks in Africa and the Arabian Peninsula. In addition to livestock, RVFV infects humans and can cause fatal hemorrhagic pneumonia. The RVFV lipid envelope contains two glycoproteins (Gn and Gc) that assemble into capsomers on the viral surface. Recent studies indicate RVFV cell entry is mediated by interaction with the glycosaminoglycan heparan sulfate (HS), which is present in abundance on the surface of most animal cells. However, the basis for this interaction is unknown. The central hypothesis of the study is that RVFV cell entry is mediated by the interaction between HS and the Gn glycoprotein. The objective of the study is to determine the kinetic and structural basis of the putative Gn-HS interaction. The rationale for this objective is that understanding the biochemical basis of RVFV Gn-HS interaction is necessary to develop novel strategies to disrupt the interaction for therapeutic purposes. The following two specific aims will be pursued: (1) determine the kinetics of the interaction between RVFV Gn and heparan sulfate, and (2) determine the structural basis of RVFV Gn-heparan sulfate interaction. Under the first aim, (i) heparin-affinity chromatography will be used to test the interaction between Gn-HS, and (ii) Surface Plasmon Resonance (SPR) will be used to determine the quantitative affinity of Gn for HS analytes. Under the second aim, (i) the established purification strategy will be refined to produce recombinant Gn suitable for crystallization, and (ii) X-ray crystallography will be used to determine the structure of Gn, with and/or without a HS ligand. The proposed research is innovative due to the detailed biochemical approach towards investigating a central feature of RVFV cell entry. The proposed research is significant because it will reveal critical insights into a fundamental aspect of RVFV virology. Successful completion of the proposed study will facilitate the long-term objective to develop multiple structure-based strategies for drug and vaccine design to prevent and treat Rift Valley Fever and mitigate its potential threat to public health.