Step 9 Analysis GROMACS Tutorial Membrane Protein via CHARMM-GUI Coordinate Files Inquiry?

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Hi I had successfully implanted my transmembrane protein into the membrane via CHARMM-GUI since I was unable to via GROMACS (specific technical issues with my protein). Is it possible to take the coordinates of the CHARMM-GUI success and proceed to the GROMACS Step 9 Analysis from the GROMACS Tutorial Membrane Protein: KALP15 in DPPC to analyze this protein-membrane system? I believe not since I would need several files generated from this Gromacs Tutorial that were not generated via CHARMM-GUI i.e. the .xtc Trajectory Compressed File was not generated during my CHARMM-GUI Gromacs Simulation process, this file is needed during the 4.-points of membrane analysis i.e. Density of the Membrane, Lateral Diffusion of Lipids etc… Maybe I could use the .xtc file generated during the Equilibration Stage of Gromacs within CHARMM-GUI, im not sure since I am just not experienced enough. Thanks if anyone is savvy enough towards answering this specific topic:), Joel🚀

You want to analyze whatever the trajectory file is that came from the unrestrained simulation. You can analyze equilibration, but there’s a reason we throw out the time spent doing it. Focus less on the file extension and more on what phase of the simulation you actually care about. Perhaps the CHARMM-GUI inputs led to a .trr file instead of .xtc? I don’t know why they would, but maybe that’s what happened and you should analyze that trajectory.

hi Justin thank you for your kind update:),

Towards the 1. Deuterium Order Parameters membrane analysis, I think the DPPC from the CHARMM-GUI generation´s numbering is different which it seemed to be upon inspection of its final coordinate file (also I have a heptamer) i.e. accordingly I received the below errors throughout. I would probably need to renumber the entire DPPC file in this case which may just be too much towards an analysis. If it something else repairable please let me know, thanks:) Joel

(base) Joels-Air:gromacs joelsubach$ gmx make_ndx -f step7_10.tpr -o sn1.ndx
:-) GROMACS - gmx make_ndx, 2022.1 (-:

Executable: /usr/local/bin/gmx
Data prefix: /usr/local
Working dir: /Users/joelsubach/Desktop/PANX1_PROJECT/MEMBRANE_IMPLANT/charmm-gui-OPM/gromacs
Command line:
gmx make_ndx -f step7_10.tpr -o sn1.ndx

Reading structure file
Reading file step7_10.tpr, VERSION 2022.1 (single precision)
Reading file step7_10.tpr, VERSION 2022.1 (single precision)
Going to read 0 old index file(s)
Analysing residue names:
There are: 3031 Protein residues
There are: 80536 Other residues
Analysing Protein…
Analysing residues not classified as Protein/DNA/RNA/Water and splitting into groups…

0 System : 358829 atoms
1 Protein : 48664 atoms
2 Protein-H : 24129 atoms
3 C-alpha : 3031 atoms
4 Backbone : 9093 atoms
5 MainChain : 12117 atoms
6 MainChain+Cb : 15022 atoms
7 MainChain+H : 15015 atoms
8 SideChain : 33649 atoms
9 SideChain-H : 12012 atoms
10 Prot-Masses : 48664 atoms
11 non-Protein : 310165 atoms
12 Other : 310165 atoms
13 DPPC : 71110 atoms
14 POT : 242 atoms
15 CLA : 214 atoms
16 TIP3 : 238599 atoms

nr : group ‘!’: not ‘name’ nr name ‘splitch’ nr Enter: list groups
‘a’: atom ‘&’: and ‘del’ nr ‘splitres’ nr ‘l’: list residues
‘t’: atom type ‘|’: or ‘keep’ nr ‘splitat’ nr ‘h’: help
‘r’: residue ‘res’ nr ‘chain’ char
“name”: group ‘case’: case sensitive ‘q’: save and quit
‘ri’: residue index

a C34

Found 547 atoms with name C34

17 C34 : 547 atoms

a c36

Found 547 atoms with name C36

18 C36 : 547 atoms

a C37

Found 547 atoms with name C37

19 C37 : 547 atoms

a C38

Found 547 atoms with name C38

20 C38 : 547 atoms

a C39

Found 547 atoms with name C39

21 C39 : 547 atoms

a C40

Found 0 atoms with name C40
Group is empty

a C41

Found 0 atoms with name C41
Group is empty

a C42

Found 0 atoms with name C42
Group is empty

a C43

Found 0 atoms with name C43
Group is empty

a C44

Found 0 atoms with name C44
Group is empty

a C45

Found 0 atoms with name C45
Group is empty

a C46

Found 0 atoms with name C46
Group is empty

a C47

Found 0 atoms with name C47
Group is empty

a C48

Found 0 atoms with name C48
Group is empty

a C49

Found 0 atoms with name C49
Group is empty

a C50

Found 0 atoms with name C50
Group is empty

del 0-21

Removed group 0 ‘System’
Removed group 1 ‘Protein’
Removed group 2 ‘Protein-H’
Removed group 3 ‘C-alpha’
Removed group 4 ‘Backbone’
Removed group 5 ‘MainChain’
Removed group 6 ‘MainChain+Cb’
Removed group 7 ‘MainChain+H’
Removed group 8 ‘SideChain’
Removed group 9 ‘SideChain-H’
Removed group 10 ‘Prot-Masses’
Removed group 11 ‘non-Protein’
Removed group 12 ‘Other’
Removed group 13 ‘DPPC’
Removed group 14 ‘POT’
Removed group 15 ‘CLA’
Removed group 16 ‘TIP3’
Removed group 17 ‘C34’
Removed group 18 ‘C36’
Removed group 19 ‘C37’
Removed group 20 ‘C38’
Removed group 21 ‘C39’

13

Group 13 does not exist
Group is empty

q

The atom names, group numbers, etc. are specific for the tutorial. You need to use the appropriate atom names and such for your system. CHARMM uses different atom naming, and you have different groups from what is in the tutorial. You can’t just type the same commands and names and expect it to work :)

Hi Justin OK thanks a bunch for the confirmation:) ill reinspect the CHARMM-GUI generated naming, groups etc. towards the Gromacs Membrane Analysis