# Glycosylation Chain ( PTM) on a protein

**URL:** <https://gromacs.bioexcel.eu/t/glycosylation-chain-ptm-on-a-protein/8928>\
**Category:** User discussions\
**Tags:** forcefield, mdrun\
**Created:** [April 19, 2024, 2:26am UTC](https://gromacs.bioexcel.eu/t/glycosylation-chain-ptm-on-a-protein/8928 "2024-04-19T02:26:25Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![GBOGH](https://avatars.discourse-cdn.com/v4/letter/g/59ef9b/32.png) [@GBOGH](https://gromacs.bioexcel.eu/u/GBOGH)\
**Post date:** [April 19, 2024, 2:26am UTC](https://gromacs.bioexcel.eu/t/glycosylation-chain-ptm-on-a-protein/8928/1 "2024-04-19T02:26:25Z")

</div>

Hi everyone!

I am trying to simulate a crystal structure (PDB) which comes with N-linked glycosylation (N-acetylglucosamine). Each N-acetylglucosamine is further linked with different sugar molecules like mannopyranose so each glycosylation exists as a chain with a few additional molecules .

Which force field shall i use? I am thinking to try with ff Gromos 54a7 but i think in the specification it can only recognize N-acetylglucosamine. Is it still okay to use Gromos 54a7?  
Would really appreciate any comment or suggestion! Thank you!