SARS-CoV-2 Spike RBD Antibody Pair 1

Capture: Llama with human IgG1 Fc
Detection: Mouse with human IgG1 Fc

Capture: 50% Glycerol, 0.01M PBS, PH 7.4
Detection: 50% Glycerol, 0.01M PBS, PH 7.4

Spike glycoprotein comprises two functional subunits responsible for binding to the host cell receptor (S1 subunit) and fusion of the viral and cellular membranes (S2 subunit). For many coronavirus (CoVs), S is cleaved at the boundary between the S1 and S2 subunits, which remain non-covalently bound in the prefusion conformation. The distal S1 subunit comprises the receptor-binding domain(s) and contributes to stabilization of the prefusion state of the membrane-anchored S2 subunit that contains the fusion machinery. S is further cleaved by host proteases at the so-called S2' site located immediately upstream of the fusion peptide in all CoVs. This cleavage has been proposed to activate the protein for membrane fusion via extensive irreversible conformational changes. However, different CoVs use distinct domains within the S1 subunit to recognize a variety of attachment and entry receptors, depending on the viral species. Endemic human coronaviruses OC43 and HKU1 attach via their S domain A to 5-N-acetyl-9-O-acetyl-sialosides found on glycoproteins and glycolipids at the host cell surface to enable entry into susceptible cells. MERS-CoV S uses domain A to recognize non-acetylated sialoside attachment receptors, which likely promote subsequent binding of domain B to the entry receptor, dipeptidyl-peptidase 4. SARS-CoV and several SARS-related coronaviruses (SARSr-CoV) interact directly with angiotensin-converting enzyme 2 (ACE2) via SB to enter target cells.

CSB-EAP33245 is a solid phase sandwich Enzyme Linked-Immuno-Sorbent Assay (Sandwich ELISA). An antibody specific for SARS-CoV-2 Spike RBD has been pre-coated onto the microwells. The SARS-CoV-2 Spike RBD protein in samples is captured by the coated antibody after incubation. Following extensive washing, another antibody HRP conjugated specific for SARS-CoV-2 Spike RBD is added to detect the captured SARS-CoV-2 Spike RBD protein. Tollowed by Tetramethyl-benzidine (TMB) reagent. Solution containing sulfuric acid is used to stop color development and the color intensity which is proportional to the quantity of bound protein is measurable at 450nm.

Human Novel Coronavirus Spike glycoprotein (S)

Study presents crystal structure of C-terminal domain of SARS-CoV-2 (SARS-CoV-2-CTD) spike S protein in complex with human ACE2 (hACE2); hACE2-binding mode similar overall to that observed for SARS-CoV. However, details at the binding interface show that key residue substitutions in SARS-CoV-2-CTD slightly strengthen the interaction and lead to higher affinity for receptor binding than SARS-CoV receptor-binding domain. PMID: 32378705
crystal structure of the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 bound to the cell receptor ACE2 PMID: 32365751
crystal structure of the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 (engineered to facilitate crystallization) in complex with ACE2 PMID: 32320687
Out of the two isolates from India compared to the isolates from Wuhan, China, one was found to harbor a mutation in its receptor-binding domain (RBD) at position 407 where, arginine was replaced by isoleucine. This mutation has been seen to change the secondary structure of the protein at that region and this can potentially alter receptor binding of the virus. PMID: 32275855
Structural modeling of the SARS-CoV-2 spike glycoprotein show similar receptor utilization between SARS-CoV-2 and SARS-CoV, despite a relatively low amino acid similarity in the receptor binding module. Compared to SARS-CoV and all other coronaviruses in Betacoronavirus lineage B, an extended structural loop containing basic amino acids were identified at the interface of the receptor binding (S1) and fusion (S2) domains. PMID: 32245784
crystal structure of CR3022, a neutralizing antibody from a SARS patient, in complex with the receptor-binding domain of the SARS-CoV-2 spike (S) protein to 3.1 A; study provides insight into how SARS-CoV-2 can be targeted by the humoral immune response and revealed a conserved, but cryptic epitope shared between SARS-CoV-2 and SARS-CoV PMID: 32225176
SARS-CoV and SARS-CoV-2 spike proteins have comparable binding affinities achieved by balancing energetics and dynamics. The SARS-CoV-2-ACE2 complex contains a higher number of contacts, a larger interface area, and decreased interface residue fluctuations relative to the SARS-CoV-ACE2 complex. PMID: 32225175
Interaction interface between cat/dog/pangolin/Chinese hamster ACE2 and SARS-CoV/SARS-CoV-2 S protein was simulated through homology modeling. Authors identified that N82 of ACE2 showed closer contact with receptor-binding domain of S protein than human ACE2. PMID: 32221306
SARS-CoV-2 S glycoprotein harbors a furin cleavage site at the boundary between the S1/S2 subunits, which is processed during biogenesis and sets this virus apart from SARS-CoV and SARS-related CoVs; determined cryo-EM structures of the SARS-CoV-2 S ectodomain trimer. PMID: 32201080
Study demonstrates that SARS-CoV-2 uses the SARS-CoV receptor ACE2 for entry and the serine protease TMPRSS2 for S protein priming. PMID: 32155444
The ACE2-B0AT1 complex exists as a dimer of heterodimers. Structural alignment of the RBD-ACE2-B0AT1 ternary complex with the S protein of SARS-CoV-2 suggests that two S protein trimers can simultaneously bind to an ACE2 homodimer. PMID: 32142651
study demonstrated SARS-CoV-2 S protein entry on 293/hACE2 cells is mainly mediated through endocytosis, and PIKfyve, TPC2 and cathepsin L are critical for virus entry; found that SARS-CoV-2 S protein could trigger syncytia in 293/hACE2 cells independent of exogenous protease; there was limited cross-neutralization activity between convalescent sera from SARS and COVID-19 patients PMID: 32132184
study determined a 3.5-angstrom-resolution cryo-electron microscopy structure of the 2019-nCoV S trimer in the prefusion conformation; provided biophysical and structural evidence that the 2019-nCoV S protein binds angiotensin-converting enzyme 2 (ACE2) with higher affinity than does severe acute respiratory syndrome (SARS)-CoV S PMID: 32075877