Crystallographic and electrophilic fragment screening of the SARS-CoV-2 main protease
NATURE COMMUNICATIONS
Authors: Douangamath, Alice; Fearon, Daren; Gehrtz, Paul; Krojer, Tobias; Lukacik, Petra; Owen, C. David; Resnick, Efrat; Strain-Damerell, Claire; Aimon, Anthony; Abranyi-Balogh, Peter; Brandao-Neto, Jose; Carbery, Anna; Davison, Gemma; Dias, Alexandre; Downes, Thomas D.; Dunnett, Louise; Fairhead, Michael; Firth, James D.; Jones, S. Paul; Keeley, Aaron; Keserue, Gyoergy M.; Klein, Hanna F.; Martin, Mathew P.; Noble, Martin E. M.; O'Brien, Peter; Powell, Ailsa; Reddi, Rambabu N.; Skyner, Rachael; Snee, Matthew; Waring, Michael J.; Wild, Conor; London, Nir; von Delft, Frank; Walsh, Martin A.
Abstract
COVID-19, caused by SARS-CoV-2, lacks effective therapeutics. Additionally, no antiviral drugs or vaccines were developed against the closely related coronavirus, SARS-CoV-1 or MERS-CoV, despite previous zoonotic outbreaks. To identify starting points for such therapeutics, we performed a large-scale screen of electrophile and non-covalent fragments through a combined mass spectrometry and X-ray approach against the SARS-CoV-2 main protease, one of two cysteine viral proteases essential for viral replication. Our crystallographic screen identified 71 hits that span the entire active site, as well as 3 hits at the dimer interface. These structures reveal routes to rapidly develop more potent inhibitors through merging of covalent and non-covalent fragment hits; one series of low-reactivity, tractable covalent fragments were progressed to discover improved binders. These combined hits offer unprecedented structural and reactivity information for on-going structure-based drug design against SARS-CoV-2 main protease.
Neutralizing and binding activities against SARS-CoV-1/2, MERS-CoV, and human coronaviruses 229E and OC43 by normal human intravenous immunoglobulin derived from healthy donors in Japan
TRANSFUSION
Authors: Kubota-Koketsu, Ritsuko; Terada, Yutaka; Yunoki, Mikihiro; Sasaki, Tadahiro; Nakayama, Emi E.; Kamitani, Wataru; Shioda, Tatsuo
Abstract
Background There are several types of coronaviruses that infect humans and cause disease. The latest is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is an emerging global threat with no current effective treatment. Normal intravenous immunoglobulin (N-IVIG) has been administered to coronavirus disease 2019 (COVID-19) patients to control severe inflammation and the cellular immune response. However, the neutralizing activity of N-IVIG against SARS-CoV-2 has not yet been fully evaluated. The aim of this study was to determine whether N-IVIG manufactured before the start of the COVID-19 pandemic contained IgG antibodies against the circulating human coronaviruses (HCoVs) that cross-react with the highly pathogenic coronaviruses SARS-CoV-1, Middle East respiratory syndrome coronavirus (MERS-CoV), and SARS-CoV-2. No cases of SARS-CoV-1 or MERS-CoV have been reported in Japan. Study Design and Methods The neutralizing and binding activities of N-IVIG against SARS-CoV-1, MERS-CoV, SARS-CoV-2, HCoV 229E, and HCoV OC43 were evaluated. Nine N-IVIG lots manufactured between 2000 and 2018, derived from donors in Japan, were tested. Binding activity was evaluated by indirect immunofluorescence assay. Results None of the N-IVIG lots tested displayed neutralizing or binding activity against SARS-CoV-1, MERS-CoV, or SARS-CoV-2. However, they displayed substantial neutralizing and binding activity against HCoV OC43 and weak neutralizing and substantial binding activity against HCoV 229E. Conclusion N-IVIG derived from healthy donors in Japan before the start of the COVID-19 pandemic had no direct effect against SARS-CoV-2. Further studies are warranted to determine the effects of N-IVIG manufactured after the start of the COVID-19 pandemic against SARS-CoV-2.