| Source: |
Escherichia coli |
| Molecular Weight: |
Approximately 25.1 kDa, a single non-glycosylated polypeptide chain containing 223 amino acid residues. |
| AA Sequence: |
RVQPTESIVR FPNITNLCPF GEVFNATRFA SVYAWNRKRI SNCVADYSVL YNSASFSTFK CYGVSPTKLN DLCFTNVYAD SFVIRGDEVR QIAPGQTGKI ADYNYKLPDD FTGCVIAWNS NNLDSKVGGN YNYLYRLFRK SNLKPFERDI STEIYQAGST PCNGVEGFNC YFPLQSYGFQ PTNGVGYQPY RVVVLSFELL HAPATVCGPK KSTNLVKNKC VNF |
| Purity: |
> 90% by SDS-PAGE. |
| Physical Appearance: |
White lyophilized (freeze-dried) powder. |
| Formulation: |
Lyophilized from a 0.2 µm filtered concentrated solution in 30% acetonitrile and 0.1% TFA. |
| Endotoxin: |
Less than 0.1 EU/μg of rSARS-CoV-2 Spike RBD as determined by LAL method. |
| Reconstitution: |
We recommend that the vial is briefly centrifuged prior to opening to bring the contents to the bottom. Reconstitute in 10 mM HCl to a concentration of 0.1-1.0 mg/mL. Stock solutions should be apportioned into working aliquots and stored at ≤ -20°C. Further dilutions should be made in appropriate buffered solutions. |
| Stability & Storage: |
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70°C as supplied.
1 month, 2 to 8°C under sterile conditions after reconstitution.
3 months, -20 to -70°C under sterile conditions after reconstitution. |
| Background: |
SARS-CoV-2, responsible for the COVID-19 pandemic, belongs to the coronavirus family, which includes four structural proteins: Spike (S), Envelope (E), Membrane (M), and Nucleocapsid (N). The Spike protein (S) facilitates viral entry by mediating membrane fusion. It is a homotrimeric glycoprotein with each monomer (~180 kDa) consisting of S1 and S2 subunits. Proteolytic cleavage of S into S1 and S2 is necessary for activation. The S1 subunit binds to the host receptor, while S2 aids in cell fusion. The receptor-binding domain (RBD) in the S1 subunit can adapt up or down conformations, with the upstate linked to higher pathogenicity. SARS-CoV-2's RBD shares 73% amino acid identity with SARS-CoV-1 but only 22% with MERS-CoV. SARS-CoV-2 S protein binds ACE2 with higher affinity than SARS-CoV-1. Structural analysis shows that only one RBD in the S1 trimer is in the "up" conformation at a time, a target for neutralizing antibodies. Polyclonal antibodies to the RBD inhibit ACE2 interaction, making RBD a key target for vaccines and therapies. The RBD can also detect neutralizing antibodies in the blood, indicating immunity. Additionally, the S protein can invade cells via the CD147/EMMPRIN receptor and mediate membrane fusion. |
