# No default Proper Dih. types

**URL:** <https://gromacs.bioexcel.eu/t/no-default-proper-dih-types/205>\
**Category:** User discussions\
**Created:** [May 28, 2020, 5:55am UTC](https://gromacs.bioexcel.eu/t/no-default-proper-dih-types/205 "2020-05-28T05:55:09Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![mijiddorj](https://avatars.discourse-cdn.com/v4/letter/m/779978/32.png) [@mijiddorj](https://gromacs.bioexcel.eu/u/mijiddorj)\
**Post date:** [May 28, 2020, 5:55am UTC](https://gromacs.bioexcel.eu/t/no-default-proper-dih-types/205/1 "2020-05-28T05:55:09Z")

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Dear GMX users,  
I would like to simulate D amino acid-containing peptides using GMX2018.7 and CHARMM36. I downloaded the last version of Charmm36 from the official site.  
grompp tells the following error message:

ERROR 1 [file topol.top, line 550]:  
No default Proper Dih. types

The line was specified the dihedral angle of CA(d-aminoacid)-C-N-CA(L-amino acid).

Is it possible to set the dihedral angle as follows?  
CTD1 C NH1 CT1 9 0.000000 6.694400 1  
CTD1 C NH1 CT1 9 180.000000 10.460000 2

Best regards,

Mijiddorj

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**Author:** ![jalemkul](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/jalemkul/32/18_2.png) [@jalemkul](https://gromacs.bioexcel.eu/u/jalemkul)\
**Post date:** [May 30, 2020, 11:00am UTC](https://gromacs.bioexcel.eu/t/no-default-proper-dih-types/205/2 "2020-05-30T11:00:08Z")

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Yes, that’s the correct approach. I’ll add the missing dihedrals for a future release.

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**Author:** ![mijiddorj](https://avatars.discourse-cdn.com/v4/letter/m/779978/32.png) [@mijiddorj](https://gromacs.bioexcel.eu/u/mijiddorj)\
**Post date:** [May 30, 2020, 11:25am UTC](https://gromacs.bioexcel.eu/t/no-default-proper-dih-types/205/3 "2020-05-30T11:25:54Z")

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Dear Justin,  
I see. Thank you very much.