| Id |
Subject |
Object |
Predicate |
Lexical cue |
| T226 |
0-281 |
Sentence |
denotes |
The S protein consists of ∼1300 aminoacids and it is composed by a N-terminal “S1”subunit (∼700 aa) and a C-terminal “S2”subunit (∼600 aa); binding to the host receptor is mediated by S1, whereas S2 induces fusion of the viral envelope with cellular membranes (Walls et al., 2017). |
| T227 |
282-408 |
Sentence |
denotes |
S1 and S2 can be further subdivided in functional segments with different roles in viral entry (Figure 4B; Tang et al., 2020). |
| T228 |
409-509 |
Sentence |
denotes |
The S1 subunit contains two subdomains, the N-terminal domain (NTD) and the C-terminal domain (CTD). |
| T229 |
510-713 |
Sentence |
denotes |
In SARS-CoV (Li, 2015) and SARS-CoV-2 (Wang et al., 2020) CTD encloses the receptor-binding domain (RBD), and the RBD section that directly contacts the receptor is named as receptor-binding motif (RBM). |
| T230 |
714-867 |
Sentence |
denotes |
The N-region of S2 contains a fusion peptide (FP), two heptapeptide repeat domains (HR1, HR2), a transmembrane domain (TM), and cytoplasmic peptide (CP). |
| T231 |
868-1035 |
Sentence |
denotes |
FP is a short segment composed of mostly hydrophobic residues, such as glycine (G) or alanine (A), which inserts in the host cell membrane to trigger the fusion event. |
| T232 |
1036-1219 |
Sentence |
denotes |
HR1 and HR2 are composed of a repetitive heptapeptide with HPPHCPC sequence, where H represents hydrophobic or bulky residues, P polar or hydrophilic residues, and C charged residues. |
| T233 |
1220-1318 |
Sentence |
denotes |
HR regions typically fold into α-helices with a hydrophobic interface that drives membrane fusion. |
