# Question Amber19SB and generation of modified residues

**URL:** https://gromacs.bioexcel.eu/t/question-amber19sb-and-generation-of-modified-residues/13415
**Category:** User discussions
**Created:** [April 26, 2026, 5:24am UTC](https://gromacs.bioexcel.eu/t/question-amber19sb-and-generation-of-modified-residues/13415 "2026-04-26T05:24:21Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![XavierB](https://avatars.discourse-cdn.com/v4/letter/x/b19c9b/32.png) [@XavierB](https://gromacs.bioexcel.eu/u/XavierB)
#### Post date: [April 26, 2026, 5:24am UTC](https://gromacs.bioexcel.eu/t/question-amber19sb-and-generation-of-modified-residues/13415/1 "2026-04-26T05:24:21Z")

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GROMACS version:2026.1  
GROMACS modification: No.

First of all, many thanks for porting the Amber19SB and its water model (OPC) to GROMACS.

I would like to generate some modified residues and add them to the force field.

Would there be a step-by-step tutorial for generating such modified residues and converting them to the Amber19SB force field, including the appropriate atom types and other required information?

Thank you for your help