SARS-CoV-2 (COVID-19) Spike S1 Protein (RBD), liquid formulation

• Species: SARS-CoV-2; Wuhan seafood market pneumonia virus
• Tags: His-Tag, C-terminal
• Sequence without tags (AA 319-541):
  MRVQPTESIVRFPNITNLCPFGEVFNATRFASVYAWNRKRISNCVADYSVLYNSASFSTF
  KCYGVSPTKLNDLCFTNVYADSFVIRGDEVRQIAPGQTGKIADYNYKLPDDFTGCVIAWN
  SNNLDSKVGGNYNYLYRLFRKSNLKPFERDISTEIYQAGSTPCNGVEGFNCYFPLQSYGF
  QPTNGVGYQPYRVVVLSFELLHAPATVCGPKKSTNLVKNKCVNF

• Expression Host: human, HEK293
• Formulation: PBS, pH 7,4
• Format: Liquid, stored and shipped at -80°C
• Purity: > 85% as determined by SDS-PAGE

The spike (S) glycoprotein of coronaviruses is essential for binding of the virus to the host cell at the beginning of the infection process. The severe acute respiratory syndrome-coronavirus (SARS-CoV) spike (S) glycoprotein is responsible for membrane fusion and is therefore required for virus entry and cell fusion. The target protein is also a major immunogen and a possible target for entry inhibitors.
The SARS-CoV-2 spike (S) protein is a large type I transmembrane protein composed of two subunits, S1 and S2. The S1 subunit contains a receptor-binding domain (RBD) responsible for binding to the host cell receptor angiotensin-converting enzyme 2 (ACE2). The S2 subunit mediates fusion between the viral and host cell membranes. The S1 RBD protein plays key parts in the induction of neutralizing-antibody and T-cell responses, as well as protective immunity.

SARS-CoV-2 Spike S1 (RBD) recognizes hACE2 (ECD) with an affinity constant of 1 nM as verified by biolayer interferometry	SARS-CoV-2 Spike S1 (RBD) is highly pure and forms stable monomers of 28 kDa as verified by SEC
Biolayer interferometry binding analysis (green lines) of hACE2 (ECD, processed), Tag-free to immobilized SARS-CoV-2 Spike S1 (RBD), His-Tag on Ni-NTA Dip and Read™ Biosensors. Grey lines correspond to a global fit of the data using a 1:1 binding model. Device: Octet RED96e, ForteBio.	Size exclusion chromatography (SEC) of purified SARS-CoV-2 Spike S1 (RBD), His-Tag protein, determination of elution profile by absorbance at 280 nm (blue line).
Fluorescence chromatogram	Activity of SARS-CoV-2 S1(RBD)
Analysis of released N-glycans by HILIC (example data). More and lot specific analytical data available on request (provided by our partner  Biofidus AG).	Activity of different SARS-CoV-2 S1(RBD) lots was determined using a Sandwich-ELISA with antibodies from Sino Biological Europe GmbH (coat: #40150-D003 and detection: #40150-D001-H).
Stability during storage at 4°C
Stability during storage at 4°C determined by functional ELISA (binding to hACE2 (ECD) – Cat# P2020-016; detection by mAb CR3022).
SDS-PAGE/Coll. Coomassie	Histogram of marked lane in gel picture

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