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Questions and answers > RNA structures (DSSR)
Analysis crashes: MD trajectory of abasic site in RNA
Marcel Heinz:
Dear Xiang-Jun,
Thanks a lot for your work and support here.
I currently have two issues with DSSR:
1.
Do you have an idea why the backbone parameter for a nucleic acids are so much faster calculated with do_x3dna than with DSSR? Analyzing a trajectory with 100k frames take for a native structure approx. 2 hours with do_x3dna. A native RNA structure with DSSR will take approx. 10 days (10k frames/day). I need to run DSSR, because my system contains an abasic site.
I used this command line:
--- Quote ---x3dna-dssr -i=mod.pdb --nmr --json --abasic -o=mod.json
--- End quote ---
2.
I also run into problems with DSSR while trying to analyze a MD trajectory (100k structures) of a ~40 NA duplex structure, containing an abasic site. DSSR crashes with an error message at frame 1630 for the abasic site with the error message
--- Quote ---model 1630 [1630 of 100000]
1630.X.U.7 0.121
1630.X.U.42 0.143
Uncaught exception 'Assertion failed' raised at [fncs_hbond.c:1762]
aborting...
--- End quote ---
The frame seems to be ok in the pdb file (s. attachement). Do you have an idea of what might be going wrong?
Best,
Marcel
xiangjun:
Hi Marcel,
Thanks for using DSSR and for your feedback on the Forum.
For your first question on the relative speed of DSSR vs. do_x3dna for calculating backbone parameters. In principle, DSSR would be slower than the 3DNA 'analyze' program since DSSR has many more (housekeeping) features calculated in the 'background'. However, the 2 hours vs 10 days difference for calculating backbone parameters as you noticed is well beyond my expectation. To investigate this issue further, could you elaborate on how you calculated the backbone parameters using do_x3dna? Does do_x3dna call the 'analyze -t' (for torsion angles) option?
For your second question, what version of DSSR were you using? This bug should have been fixed in the later releases of DSSR, as shown below:
--- Code: ---Processing file 'frame1630.pdb'
X.U.7 0.121
X.U.42 0.143
total number of nucleotides: 44
total number of base pairs: 20
total number of helices: 1
total number of stems: 3
total number of internal loops: 2
--- End code ---
Also, note that you do not need to specify the --abasic option anymore. This feature is taken into consideration by default in recent releases of DSSR.
Best regards,
Xiang-Jun
Marcel Heinz:
Thanks a lot for your very fast reply!
--- Quote from: xiangjun on August 22, 2018, 12:47:05 pm ---To investigate this issue further, could you elaborate on how you calculated the backbone parameters using do_x3dna? Does do_x3dna call the 'analyze -t' (for torsion angles) option?
--- End quote ---
I do run do_x3dna on a native RNA (no abasic site) trajectory with
--- Code: ---do_x3dna -f ../mod.pdb -s ../mod.pdb -o test -hbond
--- End code ---
and extract the dihedral information from "BackBoneCHiDihedrals_g.dat"
To investigate this further, I started the analysis an hour ago and 53,000 frames are currently analyzed with do_x3dna.
In contrast, I run DSSR now with the latest version (downloaded today) on the same pdb-trajectory with
--- Code: ---x3dna-dssr -i=mod.pdb -o=output.json --more --json --nmr
--- End code ---
and currently it runs for frame 2,100.
Based on my impression, DSSR and do_x3dna are approx. similar in analyzing the first ~1000 structures and DSSR gets slower and slower with every following structure.
As a workaround, I could cut my trajectory into 1000 structure fragments and analyze them independently, but I think the performance issue is important especially for the MD community to work with DSSR.
--- Quote from: xiangjun on August 22, 2018, 12:47:05 pm ---For your second question, what version of DSSR were you using? This bug should have been fixed in the later releases of DSSR, as shown below:
--- Code: ---Processing file 'frame1630.pdb'
X.U.7 0.121
X.U.42 0.143
total number of nucleotides: 44
total number of base pairs: 20
total number of helices: 1
total number of stems: 3
total number of internal loops: 2
--- End code ---
Also, note that you do not need to specify the --abasic option anymore. This feature is taken into consideration by default in recent releases of DSSR.
--- End quote ---
Thank you very much. Indeed, I was using an older version of DSSR and it seems to work with your latest version (frame 1630 does not crash). And thank you for the hint with the default --abasic command. I just followed the manual to this: http://x3dna.org/articles/handling-of-abasic-sites-in-dssr
Best,
Marcel
xiangjun:
Hi Marcel,
Thanks for your follow-up.
--- Code: ---do_x3dna -f ../mod.pdb -s ../mod.pdb -o test -hbond
and extract the dihedral information from "BackBoneCHiDihedrals_g.dat"
--- End code ---
Could you dig further to see what 3DNA command is being called with the above do_x3dna run? What is the -hbond option? What's the do_x3dna output looks like? Do you only need backbone torsion angles?
--- Quote ---Based on my impression, DSSR and do_x3dna are approx. similar in analyzing the first ~1000 structures and DSSR gets slower and slower with every following structure.
--- End quote ---
This is an important piece of information. I'd check if the slower performance after the first 1K structures (as you noticed) is relevant to increased memory allocation. In principle, DSSR should run each model at roughly constant speed.
--- Quote ---As a workaround, I could cut my trajectory into 1000 structure fragments and analyze them independently, but I think the performance issue is important especially for the MD community to work with DSSR.
--- End quote ---
As noted above, I'll surely look into this issue. Would it be possible that you provide me a sample MD trajectories file?
Best regards,
Xiang-Jun
Marcel Heinz:
Hi Xiang-Jun,
--- Quote from: xiangjun on August 23, 2018, 11:13:13 am ---
--- Code: ---do_x3dna -f ../mod.pdb -s ../mod.pdb -o test -hbond
and extract the dihedral information from "BackBoneCHiDihedrals_g.dat"
--- End code ---
Could you dig further to see what 3DNA command is being called with the above do_x3dna run? What is the -hbond option? What's the do_x3dna output looks like? Do you only need backbone torsion angles?
--- End quote ---
1. I honestly don't know which exact 3DNA commands are being called, but I get all structural informations in separate output files. I could refer to the official webpage where you see all the outputs listed below: https://do-x3dna.readthedocs.io/en/latest/do_x3dna_usage.html
2. The -hbond flag calculates the number of H-bonds per basepair and timeframe. The ASCII ouputfile (h-bond_g.dat) looks like this for three basepairs
--- Quote ---# Time = 1.00000
3
3
2
# Time = 2.00000
3
3
2
--- End quote ---
3. The ouput files are in ASCII format and column based, for the dihedrals, they do look like this
--- Quote ---#Strand I Strand II
#alpha beta gamma delta epsilon zeta chi ||| alpha beta gamma delta epsilon zeta chi
# Time = 1.00000
--- --- 54.5 85.7 -156.4 -76.3 -152.6 -88.4 -175.1 69.5 86.2 --- --- -114.5
-71.8 162.2 59.7 82.7 -164.5 -64.9 -163.0 -86.6 -175.1 54.5 72.1 178.6 -70.4 -136.6
-76.8 -178.7 53.6 74.4 -160.4 -64.9 -149.9 -71.7 169.9 60.6 78.4 -157.3 -57.9 -140.9
-70.2 172.9 68.1 66.9 -159.9 -59.8 -150.7 -73.8 171.8 63.5 69.0 -157.2 -61.2 -145.9
-73.0 178.7 54.8 81.2 -175.2 -59.1 -146.4 -71.9 166.1 76.6 76.4 -154.5 -64.2 -167.3
--- End quote ---
4. The overall structure parameter are of my general interest. But for now, I'm especially interested in the backbone dihedral angles.
--- Quote from: xiangjun on August 23, 2018, 11:13:13 am ---Would it be possible that you provide me a sample MD trajectories file?
--- End quote ---
The data are unpublished, so if you could provide me a way of sharing it in a non-public way (e.g. email address), I'm able to provide a native trajectory.
Just as a note: I continued the DSSR analysis since yesterday and frame 14762 is currently loaded, so I do agree to the memory issue.
Best,
Marcel
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Created and maintained by Dr. Xiang-Jun Lu [律祥俊] (xiangjun@x3dna.org)
The Bussemaker Laboratory at the Department of Biological Sciences, Columbia University.
