Stabilizing the Closed SARS-CoV-2 Spike Trimer
bioRxiv (Cold Spring Harbor Laboratory)
Abstract
Abstract The trimeric spike (S) protein of SARS-CoV-2 is the primary focus of most vaccine design and development efforts. Due to intrinsic instability typical of class I fusion proteins, S tends to prematurely refold to the post-fusion conformation, compromising immunogenic properties and prefusion trimer yields. To support ongoing vaccine development efforts, we report the structure-based design of soluble S trimers, with increased yields and stabilities, based on introduction of single point mutations and disulfide-bridges. We identify two regions in the S-protein critical for the protein’s stability: the heptad repeat region 1 of the S2 subunit and subunit domain 1 at the interface with S2. We combined a minimal selection of mostly interprotomeric mutations to create a stable S-closed variant with a 6.4-fold higher expression than the parental construct while no longer containing a heterologous trimerization domain. The cryo-EM structure reveals a correctly folded, predominantly closed pre-fusion conformation. Highly stable and well producing S protein and the increased understanding of S protein structure will support vaccine development and serological diagnostics.
Authors 9
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Affiliation as printed
Janssen Vaccines & Prevention BV, Leiden, the Netherlands
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Affiliation as printed
Janssen Vaccines & Prevention BV, Leiden, the Netherlands
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Affiliation as printed
Janssen Vaccines & Prevention BV, Leiden, the Netherlands
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Affiliation as printed
Janssen Vaccines & Prevention BV, Leiden, the Netherlands
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Affiliation as printed
Janssen Vaccines & Prevention BV, Leiden, the Netherlands
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Affiliation as printed
Janssen Vaccines & Prevention BV, Leiden, the Netherlands
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Affiliation as printed
Janssen Vaccines & Prevention BV, Leiden, the Netherlands
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Affiliation as printed
NeCEN, Leiden University, Einsteinweg 55, Leiden, the Netherlands
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Affiliation as printed
Janssen Vaccines & Prevention BV, Leiden, the Netherlands
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