# Error: No default Proper Dih. types

**URL:** <https://gromacs.bioexcel.eu/t/error-no-default-proper-dih-types/4610>\
**Category:** User discussions\
**Tags:** grompp\
**Created:** [August 15, 2022, 10:17am UTC](https://gromacs.bioexcel.eu/t/error-no-default-proper-dih-types/4610 "2022-08-15T10:17:04Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Joseph](https://avatars.discourse-cdn.com/v4/letter/j/dc4da7/32.png) [@Joseph](https://gromacs.bioexcel.eu/u/Joseph)\
**Post date:** [August 15, 2022, 10:17am UTC](https://gromacs.bioexcel.eu/t/error-no-default-proper-dih-types/4610/1 "2022-08-15T10:17:04Z")

</div>

GROMACS version: 2020.1  
GROMACS modification: No  
Conditions: no  
Force Field: Gromos 54a7  
Box type: Octahedron  
Distance from edges of box: d = 1.3

How do I resolve the error notification “No default Proper Dih. types”.  
Error message:  
ERROR 1 [file topol.top, line 58797]:  
No default Proper Dih. types

ERROR 2 [file topol.top, line 58798]:  
No default Proper Dih. types

ERROR 3 [file topol.top, line 66096]:  
No default Proper Dih. types

As a new user, I can not attach files. The protein that I was simulating was download from Alpha Fold. I removed amino acids 1119 to 1151 using pymol to reduce the size of the box.

> **[AlphaFold Protein Structure Database](https://alphafold.ebi.ac.uk/entry/Q5T5C0)**
>
> AlphaFold Protein Structure Database

Note: Disulfide bond between CYS-49 and CYS-1023

List of commands used:

1. 

gmx pdb2gmx -f Q5T5C0.pdb -o prot.gro -water spce -ignh -ter -ss

1. 

gmx editconf -f prot.gro -bt octahedron -d 1.25 -o prot\_box.gro

1. 

gmx editconf -f prot\_box.gro -o cent\_prot.gro -center 8.6985 8.201 7.902

1. 

gmx solvate -cp cent\_prot.gro -cs spc216.gro -p -o prot\_wat.gro

1. This is the command that created the error message:  
gmx grompp -f ions.mdp -c prot\_wat.gro -r prot\_wat.gro -p -o b4ions.tpr -maxwarn -1

ions.mdp file content:  
; ions.mdp - used as input into grompp to generate ions.tpr  
; Parameters describing what to do, when to stop and what to save  
integrator = steep ; Algorithm (steep = steepest descent minimization)  
emtol = 1000.0 ; Stop minimization when the maximum force \< 1000.0 kJ/mol/nm  
emstep = 0.01 ; Energy step size  
nsteps = 50000 ; Maximum number of (minimization) steps to perform

; Parameters describing how to find the neighbors of each atom and how to calculate the interactions  
nstlist = 1 ; Frequency to update the neighbor list and long range forces  
cutoff-scheme = Verlet  
ns\_type = grid ; Method to determine neighbor list (simple, grid)  
coulombtype = PME ; Treatment of long range electrostatic interactions  
rcoulomb = 1.0 ; Short-range electrostatic cut-off  
rvdw = 1.0 ; Short-range Van der Waals cut-off  
pbc = xyz ; Periodic Boundary

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<div class="post-metadata">

**Author:** ![alevilla](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/alevilla/32/439_2.png) [@alevilla](https://gromacs.bioexcel.eu/u/alevilla)\
**Post date:** [August 16, 2022, 9:45am UTC](https://gromacs.bioexcel.eu/t/error-no-default-proper-dih-types/4610/2 "2022-08-16T09:45:30Z")

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Hi,

I guess the problem is that dihedral angles are not properly defined in the directive [dihedral] in the topology file. You can check how the lines

> 58797  
> 58798  
> 66096

looks like. Here you find information on the correct format [https://manual.gromacs.org/current/reference-manual/topologies/topology-file-formats.html?highlight=force%20field%20table](https://manual.gromacs.org/current/reference-manual/topologies/topology-file-formats.html?highlight=force%20field%20table)

I have noticed that you use also -maxwarn -1. It is usually good to resolve the warning before running, if possible.

\Alessandra