Id |
Subject |
Object |
Predicate |
Lexical cue |
T87 |
0-13 |
Sentence |
denotes |
Spike protein |
T88 |
14-373 |
Sentence |
denotes |
The spike protein is a clove-shaped, type I-TM protein.[2] The spike protein has three segments that are ectodomain (ED) region, TM region, and intracellular domain, which comprises the intracellular short tail part.[2] The receptor-binding S1 domain (three S1 heads) and the membrane fusion subunit S2 (trimeric stalk) on C-terminal together comprise the ED. |
T89 |
374-1023 |
Sentence |
denotes |
Spike proteins gather in the trimeric form on the outer surface of the virion, giving it the appearance of a crown, due to which it is called CoV.[2] The spike protein plays an important role in virus entry into the host.[10] Initial interactions between the S1 domain and its host receptor (ACE2 in case of SARS-CoV and PP 4 In case of MERS-CoV) and subsequent S2 segment mediated fusion of the host and viral membranes allow the CoV- RNA genome to enter inside the host cells and thus, these proteins represent as important targets from drug discovery side.[10] The spike protein also activates the immune response of the host cell toward CoV.[10] |
T90 |
1025-1034 |
Sentence |
denotes |
S1 domain |
T91 |
1035-1136 |
Sentence |
denotes |
The main components of the S1 domain are the N-terminal domain (NTD) and the C-terminal domain (CTD). |
T92 |
1137-1444 |
Sentence |
denotes |
The S1 domain acts as a major antigen on the surface of the virus[40] and has a receptor-binding domain (RBD).[25] The 18 residues of ACE-2 interact with the RBD (contain 14 amino acids) of SARS-CoV spike protein,[45] and for this contact, K341 of ACE-2 and R453 residue of RBD play the most important role. |
T93 |
1445-1609 |
Sentence |
denotes |
If point mutated on the D454 or R441 of RBD, it disturbs the binding activity with ACE-2.[25] The S1 domain interacts with the ACE-2 or DPP-4 receptors of the host. |
T94 |
1610-2078 |
Sentence |
denotes |
Anti-ACE-2 antibody blocked viral entry and replication in Vero E6 cells.[1445] One another mechanism of virus for binding to host cell is using dendritic cell-specific intercellular adhesion molecule-3 grabbing non-integrin (DC-SIGN receptor) or L-SIGN in lymph nodes or in liver.[4647] S protein has seven (109, 118, 119, 158, 227, 589, and 699) glycosylation asparagine-linked sites, which is pivotal for both L-SIGN- or DC-SIGN-based virus entry into the host.[48] |
T95 |
2080-2090 |
Sentence |
denotes |
S2 subunit |
T96 |
2091-2184 |
Sentence |
denotes |
The S2 subunit has two heptad repeat regions (HR 1 and 2) and hydrophobic fusion peptide.[25] |
T97 |
2186-2252 |
Sentence |
denotes |
Drug designing strategies targeting S protein and its interactions |
T98 |
2253-2488 |
Sentence |
denotes |
The RBD is targeted in many drug designing studies.[25] A peptide sequence with sequence similarity to the RBD of S protein hampered S1-RBD: ACE-2 interaction and prevented entry of SARS-CoV into Vero cells (IC50 around 40 μM).[254950] |
T99 |
2489-2578 |
Sentence |
denotes |
A SARS-CoV RBD-specific antibody (FM6) failed to inhibit the occurrence of infection.[39] |
T100 |
2579-2878 |
Sentence |
denotes |
OC43-HR2P, a peptide derived from heptad repeat 2 regions of S2 domain of HCoV-OC43 and its optimized form EK1, showed pan-CoV fusion inhibition property.[39] The structure (protein data bank [PDB] ID 5ZUV and 5ZVM) shows a stable 6-helix bundle structure with α-HCoV and long β-HCoV-HR1 domain.[39] |
T101 |
2879-3074 |
Sentence |
denotes |
Chloroquine, an antimalarial agent, inhibits SERS-CoV by elevation of endosomal pH and alters the terminal glycosylation of ACE-2, which ultimately interferes with the virus receptor binding.[51] |
T102 |
3075-3282 |
Sentence |
denotes |
Other inhibitors SSAA09E2 block the S-ACE2 interaction, SSAA09E1 inhibits the host protease cathepsin L (which is important for viral entry), and SSAA09E3 prevents fusion of host and viral cell membrane.[52] |
T103 |
3283-3774 |
Sentence |
denotes |
Kao et al. identified 18 small molecules that targeted the S-ACE-2-mediated entry of virus into human cell.[53] In 293T cells expressing ACE-2, one of these agents (VE607) showed a significant inhibition of SARS-pseudovirus entry.[53] In Vero E6 cells, two other molecules tetra-O-galloyl beta-D-glucose and luteolin also inhibited SARS-pseudovirus and SARS-CoV infection.[53] In virus-infected Vero E6 cells, a siRNA against the S sequences of SARS-CoV inhibited SARS-CoV replication.[2554] |
T104 |
3775-4026 |
Sentence |
denotes |
The S230 antibody (origin: memory B-cells of SARS-CoV-infected persons) neutralizes wide spectrum of isolates of SARS-CoV.[55] S230 antibody Fab fragment binds to the SARS-CoV complex to neutralize it, and their structures are also available (PDB IDs: |
T105 |
4027-4131 |
Sentence |
denotes |
6NB6, 6NB7, and 6NB8.[55] The monoclonal antibody, m396, has a competitive role for RBD binding (PDB ID: |
T106 |
4132-4142 |
Sentence |
denotes |
2DD8).[56] |
T107 |
4143-4473 |
Sentence |
denotes |
Monoclonal antibody can be generated by immunizing the spike protein of SERS-CoV (transgenic mice) or from the B-cells of CoV-infected persons.[25] Spike-specific monoclonal antibodies 80R and CR301 block the S-ACE-2 interactions and thus neutralize infection by human SARS-CoV (HKu39849 and Tor2) and palm civet strain (SZ3).[25] |
T108 |
4474-4670 |
Sentence |
denotes |
Mice vaccinated with SARS-n DNA showed T-cell immune response (both induction and proliferation),[57] and cytotoxic T-cell response was seen against SARS-DNA-transfected alveolar epithelial cells. |