| Id |
Subject |
Object |
Predicate |
Lexical cue |
| T288 |
0-77 |
Sentence |
denotes |
Several researchers investigated the interaction of SARS-CoV-2 RBD with ACE2. |
| T289 |
78-164 |
Sentence |
denotes |
Unfortunately, each group committed to slightly different sequences of SARS-CoV-2 RBD. |
| T290 |
165-325 |
Sentence |
denotes |
To avoid confusion, we will always report the actual sequence with respect to the S protein when the RBD under study differs from the canonical 319–541 stretch. |
| T291 |
326-440 |
Sentence |
denotes |
In vitro affinity studies revealed dissociation constants of the ACE2-RBD complex in the 1–100 nM range (Table 1). |
| T292 |
441-589 |
Sentence |
denotes |
Non univocal data are attributable to the dissimilar sequences that were investigated and/or to the immobilization procedures (Shang et al., 2020b). |
| T293 |
590-781 |
Sentence |
denotes |
In spite of this variability, SARS-CoV-2 RBD was always found to bind ACE2 4–10 fold stronger than SARS-CoV RBD (Lan et al., 2020; Shang et al., 2020b; Walls et al., 2020; Wang et al., 2020). |
| T294 |
782-999 |
Sentence |
denotes |
The affinity difference in vitro was confirmed also in vivo by the stronger binding of SARS-CoV-2 S331–524 to ACE2 expressed on cells (SARS-CoV-2: EC50 = 0.08 μg/ml vs. SARS-CoV: EC50 = 0.96 μg/ml) (Tai et al., 2020). |
| T295 |
1000-1177 |
Sentence |
denotes |
Paradoxically, however, it has been shown that the ACE2 binding affinity for the entire SARS-CoV-2 S protein is lower than or comparable to that of SARS S (Shang et al., 2020a). |
| T296 |
1178-1421 |
Sentence |
denotes |
This surprising result suggests that SARS-CoV-2 RBD, albeit more potent, is less efficiently exposed than SARS-CoV RBD by the dynamic transition between the “closed” and “open” states, probably in order to escape the immune system of the host. |
| T297 |
1422-1748 |
Sentence |
denotes |
Thus, the non-identical S1 sequences of SARS-CoV-2 and SARS-CoV reflect the molecular evolution of SARS-CoV-2 toward: (1) much stronger affinity toward ACE2, (2) reduced antigenicity of the RBD region (which is one of the most antigenic segments in the S protein), (3) greater and less specific cleavability by host proteases. |
| T298 |
1749-1866 |
Sentence |
denotes |
Taken together, these properties account for the sophisticated strategy exploited by SARS-CoV-2 to invade host cells. |
