The 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. Cryogenic electron microscopy (cryo-EM) revealed that one nanobody, Nb6, binds Spike in a fully inactive conformation with its receptor binding domains (RBDs) 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.
An ultra-potent synthetic nanobody neutralizes SARS-CoV-2 by stabilizing inactive Spike
Schoof M, Faust B, Saunders RA, Sangwan S, Rezelj V, Hoppe N, Boone M, Billesbølle CB, Puchades C, Azumaya CM, Kratochvil HT, Zimanyi M, Deshpande I, Liang J, Dickinson S, Nguyen HC, Chio CM, Merz GE, Thompson MC, Diwanji D, Schaefer K, Anand AA, Dobzinski N, Zha BS, Simoneau CR, Leon K, White KM, Chio US, Gupta M, Jin M, Li F, Liu Y, Zhang K, Bulkley D, Sun M, Smith AM, Rizo AN, Moss F, Brilot AF, Pourmal S, Trenker R, Pospiech T, Gupta S, Barsi-Rhyne B, Belyy V, Barile-Hill AW, Nock S, Liu Y, Krogan NJ, Ralston CY, Swaney DL, García-Sastre A, Ott M, Vignuzzi M, QCRG Structural Biology Consortium, Walter P, Manglik A. An ultra-potent synthetic nanobody neutralizes SARS-CoV-2 by stabilizing inactive Spike. Science. 10.1126/science.abe3255, 2020
(PMID : 33154106) (PDF)
(PMID : 33154106) (PDF)