Re: [AMBER] Problems with RMSF calculations

From: Kenneth Huang <kennethneltharion.gmail.com>
Date: Fri, 26 Jun 2020 17:50:04 -0400

Hi,

My guess is the it might not be fitting to to the first frame- you can try

parm ../../prod/pd1/wt.prmtop
trajin ../../prod/pd1/[1]wt_[2]pd.nc
trajin ../../prod/pd2/[3]wt_[4]pd.nc
rms .CA first out rms.out
atomicfluct out RMSF.dat .CA byres

Which should avoid any ambiguity of if it's fetching the wrong frame.

Best,

Kenneth

On Fri, Jun 26, 2020 at 2:49 PM <kartik.lakshmi.gmail.com> wrote:

>
>
> I have a total of 500 ns trajectory - 250 + 250 ns - starting from the
> same
> eq.rst file. I calculated the RMSF (wrt to the first frame as the
> reference)
> for this 500 ns using this cpptraj script:
>
> parm ../../prod/pd1/wt.prmtop
> trajin ../../prod/pd1/[1]wt_[2]pd.nc
> trajin ../../prod/pd2/[3]wt_[4]pd.nc
> reference ../../prod/pd1/[5]wt_[6]pd.nc 1
> rms .CA reference
> atomicfluct out RMSF.dat .CA byres
> run
>
>
> I would expect the RMSF calculated using this script to give the average
> RMSF from the two production runs but it seems that the RMSF calculated
> using the input above is not the true average of the two trajectories.
>
>
> The attached graph will make it clearer.
> comp_mean.png contains the RMSF calculated using cpptraj for the entire
> PD1
> and PD2 and for PD1 + PD2. I have also plotted here the mean RMSFs (for
> 10ns
> chunks) for PD 1 and PD 2 that I calculated using python. Am I using the
> RMSF script incorrectly? I want to calculate the residue-wise
> fluctuations
> of the Ca atoms of the peptide backbone of my entire simulation (i.e.
> PD 1
> and 2 combined).
>
>
> Thanks a lot in advance for all the help!
>
> Kartik Lakshmi Rallapalli
>
> References
>
> 1.
> https://urldefense.com/v3/__http:/wt_pd.nc__;!!Mih3wA!RkWVHZ9uzYaTsfRwSkKOl8GwVSF_aGB56sRRlI2gEzyf_i_Lj7VJPgwZCZ9m$
> 2. http://pd.nc/
> 3.
> https://urldefense.com/v3/__http:/wt_pd.nc__;!!Mih3wA!RkWVHZ9uzYaTsfRwSkKOl8GwVSF_aGB56sRRlI2gEzyf_i_Lj7VJPgwZCZ9m$
> 4. http://pd.nc/
> 5.
> https://urldefense.com/v3/__http:/wt_pd.nc__;!!Mih3wA!RkWVHZ9uzYaTsfRwSkKOl8GwVSF_aGB56sRRlI2gEzyf_i_Lj7VJPgwZCZ9m$
> 6. http://pd.nc/
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> http://lists.ambermd.org/mailman/listinfo/amber
>


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Received on Fri Jun 26 2020 - 15:00:03 PDT
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