Figure 4. Agonist efficiency versus head-group volume.
Efficiencies were calculated from CRCs (n=13) or from single-channel
kinetics (n=5). Crosses mark centroids of two clusters: η=52±2%,
volume=70±8 A3 (red) and η=40±5%, volume=101±11.2
A3 (blue). Ebx from CRC analysis (gray) was excluded
from the cluster analysis. Larger-volume agonists have lower
efficiencies.