NMR studies of SARS-CoV-2 accessory proteins

Form and function are one, and deciphering structure provides the fundamentals to interfere with function, as central in the context of infection. We here propose to reveal the structures of a group of proteins which the SARS-CoV-2 virus, causing the current pandemic, carries on a non-essential basis, hence their name: accessory proteins. We concentrate on these proteins for two reasons. First, and most importantly, a significant body of evidence has accumulated that points an accusing finger to the accessory proteins and their contribution to viral fitness through modulating the host response to virus infection. Them being the most varying elements in coronaviruses supports this role, since SARS-CoV-2 carries accessory proteins not observed in other human viruses before. Second, the large majority of accessory proteins are small, and often membrane-interacting. NMR is here the method of choice, and notably solid-state NMR. We will combine NMR with cell-free synthesis of the protein samples, an approach which has the central advantages of producing even complex proteins often in well-folded form, and to allow for fast screening of candidate proteins and conditions. Analysis of the samples is enabled by highest magnetic fields and most recent NMR methodology allowing to analyze as few as 100 micrograms of protein, compatible with the quantities obtained from cell-free synthesis. The two PIs on this proposal have a long-standing collaboration (85 common papers), and are strongly committed since several years to this new approach, particularly also through A. Böckmann being a guest scientist at ETH (2020-2023). They plan to apply it here to SARS-CoV-2 accessory proteins to contribute in the fight against this emerging pathogen.