We thank the reviewer for this excellent suggestion. We have now measured the decay time constants for the NMDA-EPSCs before and after TCN-201. The graph of the data is shown in a new figure in the supplement, Fig. S4. The finding is insightful, and so we have added a paragraph relating to it in the results section, lines 520-536.
Nonetheless, in the presence of native GluN2A, molecular replacement of native GluN2B with GoF and LoF GluN2B mutants all led to similar functional incorporation into synaptic receptors, more rapidly decaying NMDA-EPSCs and greater inhibition by TCN-201, a selective antagonist of GluN2A-containing NMDA receptors.