Journal: bioRxiv / Year: 2020 Title: Bi-paratopic and multivalent human VH domains neutralize SARS-CoV-2 by targeting distinct epitopes within the ACE2 binding interface of Spike. Authors: Colton J Bracken / Shion A Lim / Paige Solomon / Nicholas J Rettko / Duy P Nguyen / Beth Shoshana Zha / Kaitlin Schaefer / James R Byrnes / Jie Zhou / Irene Lui / Jia Liu / Katarina Pance / ...Authors: Colton J Bracken / Shion A Lim / Paige Solomon / Nicholas J Rettko / Duy P Nguyen / Beth Shoshana Zha / Kaitlin Schaefer / James R Byrnes / Jie Zhou / Irene Lui / Jia Liu / Katarina Pance / / Xin X Zhou / Kevin K Leung / James A Wells / Abstract: Neutralizing agents against SARS-CoV-2 are urgently needed for treatment and prophylaxis of COVID-19. Here, we present a strategy to rapidly identify and assemble synthetic human variable heavy (VH) ...Neutralizing agents against SARS-CoV-2 are urgently needed for treatment and prophylaxis of COVID-19. Here, we present a strategy to rapidly identify and assemble synthetic human variable heavy (VH) domain binders with high affinity toward neutralizing epitopes without the need for high-resolution structural information. We constructed a VH-phage library and targeted a known neutralizing site, the angiotensin-converting enzyme 2 (ACE2) binding interface of the trimeric SARS-CoV-2 Spike receptor-binding domain (Spike-RBD). Using a masked selection approach, we identified 85 unique VH binders to two non-overlapping epitopes within the ACE2 binding site on Spike-RBD. This enabled us to systematically link these VH domains into multivalent and bi-paratopic formats. These multivalent and bi-paratopic VH constructs showed a marked increase in affinity to Spike (up to 600-fold) and neutralization potency (up to 1400-fold) on pseudotyped SARS-CoV-2 virus when compared to the standalone VH domains. The most potent binder, a trivalent VH, neutralized authentic SARS-CoV-2 with half-minimal inhibitory concentration (IC ) of 4.0 nM (180 ng/mL). A cryo-EM structure of the trivalent VH bound to Spike shows each VH domain bound an RBD at the ACE2 binding site, explaining its increased neutralization potency and confirming our original design strategy. Our results demonstrate that targeted selection and engineering campaigns using a VH-phage library can enable rapid assembly of highly avid and potent molecules towards therapeutically important protein interfaces.
History
Deposition
Aug 25, 2020
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Header (metadata) release
Oct 7, 2020
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Map release
Oct 7, 2020
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Update
Nov 13, 2024
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Current status
Nov 13, 2024
Processing site: RCSB / Status: Released
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Structure visualization
Movie
Surface view with section colored by density value
Model: UltrAuFoil R1.2/1.3 / Material: GOLD / Mesh: 200 / Support film - Material: CARBON / Support film - topology: HOLEY / Pretreatment - Type: GLOW DISCHARGE / Pretreatment - Time: 30 sec. / Pretreatment - Atmosphere: AIR
Vitrification
Cryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 277 K / Instrument: FEI VITROBOT MARK IV
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Electron microscopy
Microscope
FEI TITAN KRIOS
Image recording
Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Average electron dose: 78.0 e/Å2
Electron beam
Acceleration voltage: 300 kV / Electron source: FIELD EMISSION GUN
Electron optics
Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD
Experimental equipment
Model: Titan Krios / Image courtesy: FEI Company
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Image processing #1
Image processing ID
1
Startup model
Type of model: NONE
Final reconstruction
Resolution.type: BY AUTHOR / Resolution: 6.0 Å / Resolution method: OTHER Details: This reconstruction is a Gaussian low pass filtered map of a 3.2A gold standard FSC map, to better account for the VH density. The model was fit and relaxed into this map. Number images used: 21000
Initial angle assignment
Type: RANDOM ASSIGNMENT
Final angle assignment
Type: MAXIMUM LIKELIHOOD
FSC plot (resolution estimation)
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Image processing #2
Image processing ID
2
Startup model
Type of model: NONE
Final reconstruction
Resolution.type: BY AUTHOR / Resolution: 3.2 Å / Resolution method: FSC 0.143 CUT-OFF Details: Same reconstruction as above but filtered based on the gold standard FSC to 3.2A. Shows high resolution features but density for the low occupancy VH is poorly resolved. Number images used: 21000
In the structure databanks used in Yorodumi, some data are registered as the other names, "COVID-19 virus" and "2019-nCoV". Here are the details of the virus and the list of structure data.
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