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Parametrizing a new molecule based on known fragments
- l_karami
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Thanks for your answer.
If I want to consider C5-CO-AAVVLLWEE and C10-CO-AAVVLLWEE, are they sensible?
Best,
Leila
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- Pim
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- l_karami
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Thanks for quick reply.
I have a question about C15-CO part of C15-CO-AAVVLLWEE.
Your suggestion about C15-CO-AAVVLLWEE was as follows.
"I would map the aliphatic part to four beads as it's 17 heavy atoms. The first 12 carbons should be 3 C1 particles, the C-C-C-CO- you can debate about, maybe it can be Na."
There is another possibility:
C-C-C-C-C, C-C-C-C, C-C-C-C-, C-C-C-O
What is difference between your suggestion and my case (another possibility)?
Which of them is appropriate for CG mapping.
Best,
Leila
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- Pim
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- l_karami
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I am doing CG MD simulation (self-assembly of peptide amphiphile). I viewed trajectory file. I have pbc problem:
ln.sync.com/dl/f9182b590/2eejeayz-54nxm996-t2iu8fn2-mg8i7htv
I used the following commands:
gmx_mpi trjconv -f a.xtc -s a.tpr -n index.ndx -o nojump.xtc -pbc nojump
gmx_mpi trjconv -f nojump.xtc -s a.tpr -n index.ndx -o new.xtc -pbc mol -center
But pbc problem was not solved.
ln.sync.com/dl/e48ff49a0/2cj5tgh7-cy9azz2x-2a9nr9n5-fmftabsv
Is my manner true?
How to resolve this issue?
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- riccardo
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gmx_mpi trjconv -f a.xtc -s a.tpr -n index.ndx -o whole.xtc -pbc whole
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- l_karami
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Thanks for your answer.
After using -pbc whole, the problem was not solved:
ln.sync.com/dl/3fcb57130/e6d5ki2j-jwgs2pai-pe6c55zk-huzt2y33
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- Pim
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If you want a better visualization, you can use VMD to display the adjacent simulation box image (Periodic menu in Graphical Representations). If you really need to have your big cluster in the center of your box, you could use -pbc mol first and then -pbc cluster, or isolate it with gmx clustsize and use editconf -princ (tips on this procedure are in the analysis section of the self-assembly tutorial, cgmartini.nl/index.php/tutorials-general...eptide-gmx5#Analysis )
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- l_karami
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Thanks for your answer.
*** I tried the Periodic menu in Graphical Representations in VMD. It was good.
*** I used -pbc mol first and then -pbc cluster -center. I have a better visualization, now.
*** The link you suggested about the analysis section of the self-assembly tutorial, I encountered with " you are not authorised to view this resource ". Why???
I have another question. There are 10 aminoacids in my structure. I want to see them with bonds using the cg_bonds.tcl in trajectory file using vmd.
source cg_bonds.tcl
After using the following commands:
cg-bonds -top *.top -topoltype martini
I encountered with:
atomsel: setbonds: Need one bondlist for each selected atom
==============================================================
after using following commands:
cg-bonds -tpr *.tpr -topoltype martini
I encountered with:
couldn't write file "/dev/null": no such file or directory
How to resolve that?
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- Pim
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For CG_bonds, you have to specify all flags at the same time, so cg_bonds -tpr *.tpr -top *.top -topoltype martini -gmx /path-to/gmxdumpscript
For Gromacs 5, unfortunately gmx dump is not the same as previous gmxdump.
You will need a script somewhere that you can refer to in the above command. The script is very simple and as follows:
#!/bin/bash
source /usr/local/gromacs-2016.1/bin/GMXRC
gmx dump $@
And then of course you have to change the "source" line to where your version of gromacs is stored. I'm not sure it will work 100% even if you do everything correctly, so do not despair if not.
Hopefully at the end of the month we will have tutorials for both the analysis and the visualisation online for GMX 5, but hopefully you can use the above until then.
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- l_karami
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Thanks for your answer.
I did every things you said step by step for gmx 5. But problem was not solved.
I transferred my files to the linux system with Rocks OS and gromacs 4.5.4.
According to the example in cg_bond.tcl file, I used following command in TkConsole of VMD:
cg_bonds -tpr *.tpr -top *.top -topoltype martini -gmx /opt/bio/gromacs/bin/gmxdump
But again I encountered with:
atomsel: setbonds: Need one bondlist for each selected atom
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- Pim
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Pim
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- l_karami
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I get a new.tpr file using gmx_mpi convert-tpr containing only solute.
After using the following command:
cg_bonds -tpr new.tpr -topoltype martini -gmx /opt/bio/gromacs/bin/gmxdump
I encountered with:
child process exited abnormally
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- Pim
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1. Can you try on the trajectory with water molecules instead of the trajectory without water and the converted tpr?
2. Which version of gmx did you use for the simulations? Which version of gmxdump are you now calling?
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- l_karami
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1. My systems is very large (40 GB). Trying trajectory with water is hard for me. I will try that.
In fact for simulation, I used a cluster that I access it by remote.
For viewing the trajectory directly in vmd in linux, I used another system. Thus, I use trajectory file without waters. Transferring the trajectory with waters from the cluster to my system is hard and time consuming.
2. The version of gmx did I use for the simulations is 5.1.3
The version of gmxdump I now calling is 4.5.4
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- Pim
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If you specify both tpr and top you usually don't need the gmxdump. So the last thing you can try is cg_bonds -tpr topol.tpr -top topol.top without -gmx
Otherwise, you have to compile gromacs 5 somewhere and then use the script I gave yesterday to link gmxdump to the correct gromacs 5 version.
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- Pim
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- l_karami
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I used trajectory with water molecules and only cg_bonds -tpr topol.tpr -top topol.top in VMD. My problem was solved. Thanks for your step by step guidance.
My system is CH3-(CH2)15-CO-AAVVLLLWEE. I want to see peptide part (AAVVLLLWEE) of the last frame of CG MD simulation using the cg_bonds in VMD.
For one peptide, in my system:
ln.sync.com/dl/3d9367d00/3axb6ct5-vi7g53z9-criuhpce-h8vf23z6
I want to have my peptide same as the figure in some papers (yellow circle):
ln.sync.com/dl/4d471dc30/qac9mir8-gur5m8xy-xs5iu7gs-f242rjac
How to obtain that?
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- Pim
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If you download cg_secondary_structure.tcl and the POSIX LA package described there, you can draw some (basic) beta sheet ribbons.
I don't know how the people in your paper did it, maybe with backmapping?
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