Recombinant SARS-CoV-2, RBD Protein (Gamma, P.1, Brazil Variant)

This gamma variant of SARSCoV2 (also known as P.1) emerged in Brazil and has 17 unique mutations, including 3 in the Receptor Binding Domain (RBD) of the spike protein.¹ The RBD mutation is K417T, E484K, N501Y, A570D. This variant has been detected in multiple countries, including the United States.

Severe acute respiratory syndrome coronavirus 2 (SARSCoV2), the causative agent of coronavirus disease 2019 (COVID19), is an enveloped, singlestranded, positivesense RNA virus that belongs to the Coronaviridae family ². The SARSCoV2 genome, which shares 79.6% identity with SARSCoV, encodes four essential structural proteins: the spike (S), envelope (E), membrane (M), and nucleocapsid protein (N) ³. The S protein is a transmembrane, homotrimeric, class I fusion glycoprotein that mediates viral attachment, fusion, and entry into host cells ⁴. Each ~180 kDa monomer contains two functional subunits, S1 (~700 a.a) and S2 (~600 a.a), that mediate viral attachment and membrane fusion, respectively. S1 contains two major domains, the Nterminal (NTD) and Cterminal domains (CTD). The CTD contains the receptorbinding domain (RBD), which binds to the angiotensinconverting enzyme 2 (ACE2) receptor on host cells ⁴⁶. Although both SARSCoV and SARSCoV2 bind the ACE2 receptor, the RBDs only share ~73% amino acid identity, and the SARSCoV2 RBD binds with a higher affinity compared to SARSCoV ^4,7. The RBD is dynamic and undergoes hingelike conformational changes, referred to as the “down” or “up” conformations, which hide or expose the receptorbinding motifs, respectively ⁸. Following receptor binding, S1 destabilizes, and TMPRSS2 cleaves S2, which undergoes a pre to postfusion conformation transition, allowing for membrane fusion ^9,10.

RVQPTESIVRFPNITNLCPFGEVFNATRFASVYAWNRKRISNCVADYSVLYNSASFSTFKCYGVSPTKLNDLCFTNVYADSFVIRGDEVRQIAPGQTGTIADYNYKLPDDFTGCVIAWNSNNLDSKVGGNYNYLYRLFRKSNLKPFERDISTEIYQAGSTPCNGVKGFNCYFPLQSYGFQPTYGVGYQPYRVVVLSFELLHAPATVCGPKKSTNLVKNKCVNFNFNGLTGTGVLTESNKKFLPFQQFGRDIADTTDAVRDPQTLEILDITPCS

Sterile Liquid

The predicted molecular mass is ~33 kDa.

~33 kDa

This recombinant protein is aseptically packaged and formulated in 0.01 M phosphate buffered saline (PBS) pH 7.2 7.4, 150 mM NaCl with no carrier protein, potassium, calcium or preservatives added. Due to inherent biochemical properties of proteins, certain products may be prone to precipitation over time. Precipitation may be removed by aseptic centrifugation and/or filtration.

This recombinant protein may be stored as received at 28°C for up to one month. For longer term storage, aseptically aliquot in working volumes without diluting and store at 80°C. Avoid Repeated Freeze Thaw Cycles.

Next Day Ice Pack

1. Center for Disease Control and Prevention. 2020
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3. Wu, F., Zhao, S., Yu, B. et al. Nature 579, 265–269. 2020.
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5. Walls AC, Park YJ, Tortorici MA, Wall A, McGuire AT, Veesler D. Cell. 181(2):281292.e6. 2020.
6. Li W, Zhang C, Sui J, et al. EMBO J. 24(8):16341643. 2005.
7. Shang, J., Ye, G., Shi, K. et al. Nature 581, 221–224. 2020.
8. Gui M, Song W, Zhou H, et al. Cell Res. 27(1):119129. 2017.
9. Walls AC, Tortorici MA, Snijder J, et al. Proc Natl Acad Sci U S A. 114(42):1115711162. 2017.
10.. Hoffmann M, KleineWeber H, Schroeder S, et al. Cell. 181(2):271280.e8. 2020.