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. 2021 Aug 26;10:e70658. doi: 10.7554/eLife.70658

Table 1. Affinity and kinetic data for RBD variants and ACE2 variants.

Mean and SD of the koff, kon, calculated KD, and equilibrium KD values for all RBD variants binding all ACE2 variants. For most measurements n = 3, the exceptions were RBD WT/ACE2 WT equilibrium KD measurements (n = 24) and other RBD WT measurements (n = 6). UK2 refers to the VOC-202102–02 variant.

koff (s–1) SD kon (µM–1 s–1) SD KD calc. (nM) SD KD equi. (nM) SD
 RBD over WT ACE2
WT 0.0668 0.00113 0.90 0.05 74.4 4.0 62.6 7.7
K417N 0.177 0.00416 0.49 0.05 364 29 349 10
K417T 0.126 0.00510 0.55 0.04 230 23 226 19
S477N 0.0348 0.00037 0.81 0.03 42.9 2.1 42.6 3.0
E484K 0.0818 0.00183 1.54 0.03 53.1 1.7 52.6 2.0
N501Y (Alpha) 0.0111 0.00017 1.59 0.04 7.0 0.25 5.5 2.4
K417N/E484K 0.251 0.00799 1.02 0.07 247 23 251 23
K417T/E484K 0.168 0.00573 1.10 0.05 153 12 147 8.6
E484K/N501Y (UK2) 0.0118 0.00037 2.33 0.10 5.1 0.36 3.7 2.7
K417N/E484K/N501Y (Beta) 0.0291 0.00076 1.46 0.06 20.0 0.70 17.4 3.1
K417T/E484K/N501Y (Gamma) 0.0211 0.00021 1.56 0.07 13.5 0.45 12.2 3.4
 RBD over S19P ACE2
WT 0.0298 0.00039 1.50 0.12 20.0 1.3 30.5 2.2
K417N 0.0782 0.00284 0.72 0.04 108 2.8 129 8.2
K417T 0.0521 0.00196 0.69 0.02 75.8 4.7 87.8 7.0
S477N 0.0257 0.00016 1.05 0.07 24.6 1.7 30.3 2.7
E484K 0.0325 0.00031 2.02 0.08 16.2 0.55 20.8 1.3
N501Y (Alpha) 0.0051 0.00004 2.31 0.09 2.2 0.09 3.5 0.4
K417N/E484K 0.0961 0.00198 1.28 0.11 75.6 7.1 91.3 6.5
K417T/E484K 0.0660 0.00255 1.45 0.03 45.5 2.5 53.8 1.5
E484K/N501Y (UK2) 0.0051 0.00008 3.10 0.10 1.7 0.05 3.4 0.4
K417N/E484K/N501Y (Beta) 0.0122 0.00009 2.16 0.03 5.7 0.07 10.4 1.2
K417T/E484K/N501Y (Gamma) 0.0085 0.00007 2.11 0.05 4.0 0.07 6.1 1.3
RBD over K26R ACE2
S477N 0.0240 0.00009 1.07 0.05 22.6 1.1 33.4 1.3
WT 0.0500 0.00062 1.60 0.16 31.4 2.6 48.8 2.5
K417N 0.154 0.00789 0.88 0.07 175 8.1 237 15
K417T 0.101 0.00079 0.81 0.12 127 17.4 154 2.8
S477N 0.0240 0.00009 1.07 0.05 22.6 1.1 33.4 1.3
E484K 0.0587 0.00109 2.03 0.03 28.9 1.0 35.9 1.5
N501Y (Alpha) 0.0081 0.00002 2.34 0.09 3.5 0.15 7.5 1.5
K417N/E484K 0.191 0.00481 1.48 0.15 130 9.4 166 11
K417T/E484K 0.135 0.00407 1.53 0.02 88.0 3.9 105 0.7
E484K/N501Y (UK2) 0.0085 0.00018 3.06 0.23 2.8 0.17 6.4 0.3
K417N/E484K/N501Y (Beta) 0.0234 0.00040 2.13 0.05 11.0 0.28 18.7 2.0
K417T/E484K/N501Y (Gamma) 0.0164 0.00028 2.21 0.06 7.4 0.33 15.3 0.8