# Charmm gui accuracy and forcefield version in it?

**URL:** https://gromacs.bioexcel.eu/t/charmm-gui-accuracy-and-forcefield-version-in-it/1433
**Category:** User discussions
**Created:** [January 13, 2021, 10:07am UTC](https://gromacs.bioexcel.eu/t/charmm-gui-accuracy-and-forcefield-version-in-it/1433 "2021-01-13T10:07:09Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![rakesh](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@rakesh](https://gromacs.bioexcel.eu/u/rakesh)
#### Post date: [January 13, 2021, 10:07am UTC](https://gromacs.bioexcel.eu/t/charmm-gui-accuracy-and-forcefield-version-in-it/1433/1 "2021-01-13T10:07:09Z")

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GROMACS version: latest  
GROMACS modification: Yes/No  
Here post your question  
I have simulated a peptide with alternating L and D amino acid residue in lipid bilayer using files that i got from charmm-gui input generator.  
\*\*Forcefield that i opt at last step of input generator is - CHARMM36 (is it the recent version charmm36 july 2020)  
\*\*is the force-field taken into consideration in charmm-gui is the latest version of CHARMM-36

My aim of simulating these protein with alternating L and D amino acid residue is to scrutinize the conformational space of all residue in ramachandran plot after 100ns.

\*\*how can i achieve the appropriate result that i am seeking for ?

I am attaching the input that i got (LD14\_updated folder in drive link ) and some files after 100ns md run with ramachandran plot of ALA7 and DALA12.  
you can see the some conformation of these residue are in disallowed region in ramachandran plot

step7\_1 is nomenclature for files after 100ns mdrun in gromacs.

[https://drive.google.com/drive/folders/12D-ikoZYjbNN09XxpBZfvkbLYa8dX49U?usp=sharing](https://drive.google.com/drive/folders/12D-ikoZYjbNN09XxpBZfvkbLYa8dX49U?usp=sharing)

Hoping for a help