Full Spike (S), ectodomain, S1, and RBD Coding Sequences

structure SARS-CoV-2 spike gene and protein

Spike (S) is a multifunctional glycoprotein that mediates SARS-CoV-2 (2019-nCoV) entry into the target cells [1, 2]. Most of the current knowledge about the SARS-CoV-2 Spike is based on analogies with findings on the previously identified SARS-CoV Spike. At the surface of the virus, Spike is a clove-shaped trimer. Each Spike protomer contains three segments: a large ectodomain, a transmembrane anchor (TM), and a short intracellular tail (IC) [1-3]. The Spike ectodomain contains three critical elements:

  • the S1 subunit contains an N-terminal (S1-NTD) and a C-terminal (S1-CTD) subdomains. The S1 "closed" conformation exerts a physical constraint on the S2 subunit until specific proteases cleave the S1/S2 and S2' sites [3].
  • the RBD (receptor binding domain) is located in the S1-CTD region and is buried in the inner S1 head-trimer. The S1 "open" conformation is expected to be necessary for binding to the ACE2 receptor at the surface of host target cells [3, 4].
  • the S2 subunit forms a trimeric stalk. It contains a fusion peptide (FP) and two heptad repeats (HR1 and HR2), which operate the fusion of viral and host membranes [3, 4].

Depending on your applications, InvivoGen offers genes encoding SARS-CoV-2 full-length Spike or fragments, from the Wuhan-Hu-1 isolate (D614) in different plasmids:

pUNO1 expression vector

  • Designed for mammalian cell expression of the full Spike glycoprotein
  • Contains the native (wild-type) Spike coding sequence
  • Contains the virus signal sequence

pUNO1His or pUNO1Fc production vectors

  • Designed for mammalian cell production and secretion of the Spike ectodomain, S1, or RBD
  • Express an optimized Spike coding sequence with CHO codon usage
  • Contain an exogenous signal sequence for extracellular secretion
  • Feature a C-terminal His- or Fc-tag to facilitate the detection and/or the purification of the Spike ectodomain, S1, or RBD




1. Li F., 2016. Structure, function, and evolution of coronavirus spike proteins. Annu. Rev. Virol. 3:237-261.
2. Li F. et al., 2005. Structure of SARS coronavirus spike receptor-binding domain complexed with receptor. Science. 309:1864-1868.
3. Walls A.C. et al., 2020. Structure, function, and antigenicity of the SARS-CoV-2 spike glycoprotein. Cell. 181(2):281-292.e6.
4. Hoffmann M. et al., 2020. SARS-CoV-2 cell entry depends on ACE2 and TMPRSS2 and is blocked by a clinically proven protease inhibitor. Cell. 181:1-16.

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