MM-PBSA value coming positive

[akr rathee]

Dear Mario Ernesto,

I am sharing the MMPBSA run - Output file in a final_result.dat file and along with the mmpbsa.in script file. I have found my GBSA values come negatively but my compound MMPBSA value come positive.

How is it ?? and what is the reason behind it. 

Your comments are valuable

Thankyou in advance.
AKR 

[Mario Sergio Valdes]

In some cases, the EDISPER term may be overestimated. When inp=2 is defined for PB the non-polar solvation component is calculated differently from GB. In one case it is modeled as a single term linearly proportional to SASA, while in PB it is decomposed into ENPOLAR also linearly proportional to SASA and the dispersion term (EDISPER). You may wish not to calculate this term. Please review the discussions we have had here in the group, this issue on Github (https://github.com/Valdes-Tresanco-MS/gmx_MMPBSA/issues/273), the explanation here (https://valdes-tresanco-ms.github.io/gmx_MMPBSA/dev/Q%26A/calculations/#possible-solutions_2) and the variables involved (https://valdes-tresanco-ms.github.io/gmx_MMPBSA/dev/input_file/#basic-input-options_2).
To not include the EDISPER term, set the variable inp=1 in the input file and perform the calculation again. Note that you do not have to run GB again.

HTH!

Mario S.