Experimentally determined and predicted binding affinity ranges of the 23 opioids docked at the μOR.

The 8 fentanyl derivatives and 7 fentanyl congeners are listed first and ordered by increasing binding affinity, and the 8 morphine derivatives are listed last. The green labels indicate that the model correctly predicted the binding concentration regime, yellow indicates that the model predicted the compound to bind stronger than the measured Ki, and red indicates that the model predicted the compound to bind less strongly than the measured Ki.