“Pulling factor” k, empirically
defined as the slope of linear correlation between ΔΔG and insertion length, for each transition along the NMDAR
activation pathway. (A) Plots correlating ΔΔG (kcal mol–1) and insertion length for GluN2A in
the C2 → C1 transition. Also shown is
the slope k, in kcal mol–1 nm–1, for linear fits to the first three (black) or four
(gray) points. (B) Pulling factors, using three-point analysis, for
all the transitions along the activation pathway. C1, C2, C3, O1, and O2 denote kinetic
substates along the activation pathway. Reproduced with permission
from ref (18). Copyright
2014 Nature Publishing Group.