# Newest CHARMM36 port for GROMACS

**URL:** https://gromacs.bioexcel.eu/t/newest-charmm36-port-for-gromacs/868
**Category:** Third party tools and files
**Tags:** forcefield
**Created:** [September 25, 2020, 7:08am UTC](https://gromacs.bioexcel.eu/t/newest-charmm36-port-for-gromacs/868 "2020-09-25T07:08:22Z")
**Posts on this page:** 1
**Showing post:** 14

<div class="post-metadata">

### 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: [March 16, 2023, 1:16pm UTC](https://gromacs.bioexcel.eu/t/newest-charmm36-port-for-gromacs/868/14 "2023-03-16T13:16:56Z")

</div>

You need to use the `-ter` option and interactively choose from the prompts as to which termini you want. For polypeptides, you typically want NH3+. The MET1 patch is for carbohydrates, but `pdb2gmx` thinks it’s the best match because it matches the MET residue name. In this case, it’s the program trying to be too smart (though there are reasons for it that are typically associated with GLY residues).

---

_[View the full topic](https://gromacs.bioexcel.eu/t/newest-charmm36-port-for-gromacs/868)._