Citation
- Authors: Cerutti G. et al.
- Year: 2022
- Journal: Cell Rep 38 110428
- Applications: in vitro / DNA / FectoPRO
- Cell type: Expi293F
Description: Human embryonic kidney Fibroblast
Known as: Expi 293-F, Expi, HEK-293 Expi
Method
Expression and purification of SARS-CoV-2 spike
The ectodomain with 2P and furin mutations of SARS-CoV-2 B.1.1.529 trimer was synthesized, fused to an 8 × His tag at the C terminus and then cloned into the pαH vector. To purify the S trimer protein, the expression vector was transiently transfected into Expi293 cells using FectoPRO (Polyplus-transfection SA). Two days after transfection, the S trimer protein was purified using Ni-NTA resin.
Abstract
The recently reported B.1.1.529 Omicron variant of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) includes 34 mutations in the spike protein relative to the Wuhan strain, including 15 mutations in the receptor-binding domain (RBD). Functional studies have shown Omicron to substantially escape the activity of many SARS-CoV-2-neutralizing antibodies. Here, we report a 3.1 Å-resolution cryoelectron microscopy (cryo-EM) structure of the Omicron spike protein ectodomain. The structure depicts a spike that is exclusively in the 1-RBD-up conformation with high mobility of RBD. Many mutations cause steric clashes and/or altered interactions at antibody-binding surfaces, whereas others mediate changes of the spike structure in local regions to interfere with antibody recognition. Overall, the structure of the Omicron spike reveals how mutations alter its conformation and explains its extraordinary ability to evade neutralizing antibodies.