I have performed MD simulations and obtained binding free energy using MMGBSA. Say it was -30 Kcal/mol. Later on, I separately computed entropy (T-Delta-S) for the same system. The said entropy value is scaled to the temperature. Say it was found to be -20 Kcal/mol. I did these calculations using MolAICal software.

My question is, based on this data (MMGBSA and entropy), how do we calculate final binding free energy?

will it be

1. -30 -(-20)=-10 Kcal/Mol or (if we go by equation deltaH - TdeltaS)

OR

2. -30+(-20)= -50 Kcal/mol (Simple MMGBSA+entropy)

I am open to discussion.