Spike glycoprotein (S) (K417N,E484K,N501Y), partial, recombinant Severe acute respiratory syndrome c

Organism: Severe acute respiratory syndrome coronavirus 2 (2019-nCoV) (SARS-CoV-2). Source: Mammalian cell. Expression Region: 319-541aa(K417T). Protein Length: Partial. Tag Info: C-terminal mFc-tagged. Target Protein Sequence: RVQPTESIVR FPNITNLCPF GEVFNATRFA SVYAWNRKRI SNCVADYSVL YNSASFSTFK CYGVSPTKLN DLCFTNVYAD SFVIRGDEVR QIAPGQTGTI ADYNYKLPDD FTGCVIAWNS NNLDSKVGGN YNYLYRLFRK SNLKPFERDI STEIYQAGST PCNGVEGFNC YFPLQSYGFQ PTNGVGYQPY RVVVLSFELL HAPATVCGPK KSTNLVKNKC VNF. Purity: Greater than 90% as determined by SDS-PAGE. Endotoxin: Not test. Biological Activity: n/a. Form: Liquid or Lyophilized powder. Buffer: If the delivery form is liquid, the default storage buffer is Tris/PBS-based buffer, 5%-50% glycerol. If the delivery form is lyophilized powder, the buffer before lyophilization is Tris/PBS-based buffer, 6% Trehalose, pH 8.0. Reconstitution: We recommend that this vial be briefly centrifuged prior to opening to bring the contents to the bottom. Please reconstitute protein in deionized sterile water to a concentration of 0.1-1.0 mg/mL.We recommend to add 5-50% of glycerol (final concentration) and aliquot for long-term storage at -20°C/-80°C. Our default final concentration of glycerol is 50%. Customers could use it as reference. Storage: The shelf life is related to many factors, storage state, buffer ingredients, storage temperature and the stability of the protein itself. Generally, the shelf life of liquid form is 6 months at -20°C/-80°C. The shelf life of lyophilized form is 12 months at -20°C/-80°C. Notes: Repeated freezing and thawing is not recommended. Store working aliquots at 4°C for up to one week. Relevance: [Spike protein S1]: attaches the virion to the cell membrane by interacting with host receptor, initiating the infection. Binding to human ACE2 receptor and internalization of the virus into the endosomes of the host cell induces conformational changes in the Spike glycoprotein . Binding to host NRP1 and NRP2 via C-terminal polybasic sequence enhances virion entry into host cell . This interaction may explain virus tropism of human olfactory epithelium cells, which express high level of NRP1 and NRP2 but low level of ACE2 . The stalk domain of S contains three hinges, giving the head unexpected orientational freedom . Uses human TMPRSS2 for priming in human lung cells which is an essential step for viral entry . Can be alternatively processed by host furin . Proteolysis by cathepsin CTSL may unmask the fusion peptide of S2 and activate membranes fusion within endosomes., [Spike protein S2]: mediates fusion of the virion and cellular membranes by acting as a class I viral fusion protein. Under the current model, the protein has at least three conformational states: pre-fusion native state, pre-hairpin intermediate state, and post-fusion hairpin state. During viral and target cell membrane fusion, the coiled coil regions (heptad repeats) assume a trimer-of-hairpins structure, positioning the fusion peptide in close proximity to the C-terminal region of the ectodomain. The formation of this structure appears to drive apposition and subsequent fusion of viral and target cell membranes., [Spike protein S2']: Acts as a viral fusion peptide which is unmasked following S2 cleavage occurring upon virus endocytosis., [Spike glycoprotein]: May down-regulate host tetherin (BST2) by lysosomal degradation, thereby counteracting its antiviral activity. Reference: "Structure, function, and antigenicity of the SARS-CoV-2 spike glycoprotein." Walls A.C., Park Y.J., Tortorici M.A., Wall A., McGuire A.T., Veesler D. Cell 180:1-12(2020). Function: nan