Exploring the conformational landscape of the rabies virus glycoprotein using HDX-MS.

Rabies virus, a member of the lyssavirus family, causes on the order of 60,000 deaths per year, disproportionately affecting historically exploited regions of the world. While prophylactic measures such as vaccines and immunoglobulin therapies are very effective at preventing rabies upon exposure, these treatments are very expensive and require cold-chain logistics, making them inaccessible to much of the world. Furthermore, there is no cure for rabies after the onset of symptoms, making it a death sentence for people who do not seek treatment because either they lack access or they do not suspect the animal they were bitten by was infectious. The rabies virus glycoprotein (RABV-G) is densely displayed on the surface of the virion, making it an attractive target for vaccine and drug development, yet this protein remains poorly understood. RABV-G is a highly dynamic protein that is known to reversibly sample its pre- and post-fusion conformations in equilibrium at physiological pH, making it difficult to study using many in vitro methods. Hydrogen deuterium exchange monitored by mass spectrometry (HDX-MS) is an ideal technique to probe the conformational landscape of proteins that occupy more than one conformation in solution. This work uses HDX-MS to measure the local stability of the protein when biased to both the prefusion and postfusion conformation as well as quantify the kinetics of the conformational change between the two conformations. This work will be useful in exploring how antibodies interact with the different conformations of rabies G in order to design better therapeutic strategies to combat this lethal virus.