Fig. 4: SARS2-S D614G protein binds ACE2 with higher affinity than WT S protein.
From: SARS-CoV-2 D614G spike mutation increases entry efficiency with enhanced ACE2-binding affinity
Binding affinity between dimeric ACE2 and trimeric SARS2-S WT (a, c, and e) or D614G variant (b, d, and f) (two-fold serially diluted from 71.4 nM to 1.12 nM) was evaluated at 25 °C (a and b), 30 °C (c and d), or 37 °C (e and f) using Octet RED96 instrument. The association rate constants (Kon) and dissociation rate constants (Kdis) were determined by global fitting of the experimental data using a 1:1 binding model. Equilibrium dissociation constants (KD) were obtained from Kdis∕Kon. Data shown are representative sensorgrams from two independent experiments at 25/37°C and from three independent experiments at 30°C using different protein preparations. The difference in KD and Kdis at 30°C was statistically significant (p = 0.0042 and 0.0129, respectively) by a two-tailed unpaired Student’s t-test, as shown in Supplementary Fig. 5. Source data are provided as a Source Data file.
