An ultrapotent synthetic nanobody neutralizes SARS-CoV-2 by stabilizing inactive Spike.
Michael SchoofBryan FaustReuben A SaundersSmriti SangwanVeronica V RezeljNicholas HoppeMorgane BooneChristian B BillesbølleCristina PuchadesCaleigh M AzumayaHuong T KratochvilMarcell ZimanyiIshan DeshpandeJiahao LiangMiles Sasha DickinsonHenry C NguyenCynthia M ChioGregory E MerzMichael C ThompsonDevan DiwanjiKaitlin SchaeferAditya A AnandNiv DobzinskiBeth Shoshanna ZhaCamille R SimoneauKristoffer E LeonKris M WhiteUn Seng ChioMeghna GuptaMingliang JinFei LiYanxin LiuKaihua ZhangDavid BulkleyMing SunAmber M SmithAlexandrea N RizoFrank R MossAxel F BrilotSergei PourmalRaphael TrenkerThomas H PospiechSayan GuptaBenjamin Barsi-RhyneVladislav BelyyAndrew W Barile-HillSilke NockYuwei LiuNevan J KroganCorie Y RalstonDanielle L SwaneyAdolfo García-SastreMelanie M OttMarco Vignuzzinull nullPeter WalterAashish ManglikPublished in: Science (New York, N.Y.) (2020)
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus enters host cells via an interaction between its Spike protein and the host cell receptor angiotensin-converting enzyme 2 (ACE2). By screening a yeast surface-displayed library of synthetic nanobody sequences, we developed nanobodies that disrupt the interaction between Spike and ACE2. Cryo-electron microscopy (cryo-EM) revealed that one nanobody, Nb6, binds Spike in a fully inactive conformation with its receptor binding domains locked into their inaccessible down state, incapable of binding ACE2. Affinity maturation and structure-guided design of multivalency yielded a trivalent nanobody, mNb6-tri, with femtomolar affinity for Spike and picomolar neutralization of SARS-CoV-2 infection. mNb6-tri retains function after aerosolization, lyophilization, and heat treatment, which enables aerosol-mediated delivery of this potent neutralizer directly to the airway epithelia.