# gmx\_MMPBSA does not know the atom types

**URL:** <https://gromacs.bioexcel.eu/t/gmx-mmpbsa-does-not-know-the-atom-types/5813>\
**Category:** User discussions\
**Created:** [February 16, 2023, 1:28pm UTC](https://gromacs.bioexcel.eu/t/gmx-mmpbsa-does-not-know-the-atom-types/5813 "2023-02-16T13:28:18Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![baharebamdad](https://avatars.discourse-cdn.com/v4/letter/b/9e8a1a/32.png) [@baharebamdad](https://gromacs.bioexcel.eu/u/baharebamdad)\
**Post date:** [February 16, 2023, 1:28pm UTC](https://gromacs.bioexcel.eu/t/gmx-mmpbsa-does-not-know-the-atom-types/5813/1 "2023-02-16T13:28:18Z")

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GROMACS version: 2019  
GROMACS modification no  
Dear Gromacs people,

I need to calculate the binding free energy between a metal organic framework (including Zr) and a protein. I used the OBGMX program to generate UFF force field parameters for the MOF and MD simulation has been done successfully. But, I receive the following error after running gmx\_MMPBSA program:

FATAL: Atom .R\<UFF 311\>.A\<Zr34 5\> does not have a type.  
FATAL: Atom .R\<UFF 311\>.A\<O\_3 4\> does not have a type.  
FATAL: Atom .R\<UFF 311\>.A\<O\_2 3\> does not have a type.  
FATAL: Atom .R\<UFF 311\>.A\<C\_R 2\> does not have a type.  
FATAL: Atom .R\<UFF 311\>.A\<C\_2 1\> does not have a type

May I ask you to help me in resolving the problem? Is it possible for gmx\_MMPBSA to read atom types from the atomtypes.itp file?

Best regards,  
Bahareh