do_x3dna for VMD
do_x3dna for VMD is written in Tcl language and it can be used as VMD plugin or Tcl package with VMD. It produces output files in same format as generated by GROMACS do_x3dna.
Note
do_x3dna VMD plugin does not depend on GROMACS do_x3dna. Therefore, do_x3dna for GROMACS is not necessary to run do_x3dna VMD plugin.
Following parameters are calculated using 3DNA package for each frame and written in separate files as a function of time.
Base-pairs
Hydrogen bonds between base-pairs
Base-pairs parameters
Base-steps parameters
Helical Base-steps parameters
Local helical axis
Major and minor grooves
Local helical radius
Backbone dihedral angles (
alpha
,beta
,gamma
,delta
,epsilon
,zeta
andchi
)Sugar dihedral angles (
v0
,v1
,v2
,v3
andv4
)
These files could be used with the dnaMD
module and tools for further analysis.
Download
do_x3dna package can be downloaded by either of following two steps.
Use
git
:
git clone -b master --single-branch https://github.com/rjdkmr/do_x3dna
Installation
Follow these steps to install do_x3dna as VMD plugin.
cd do_x3dna
cd vmd
cp -r do_x3dna /usr/local/lib/vmd/plugins/noarch/tcl/.
If VMD is not at default location, copy vmd/do_x3dna
in plugins/noarch/tcl/
vmd directory.
How to use?
To use do_x3dna VMD plugin, 3DNA package should be installed and $X3DNA
environment
variable (Detail is given in 3DNA manual) should be defined.
It can be either used from VMD TkConsole or through a Tcl scrip.
For example, below section can be used directly in VMD TkConsole or save it as a tcl script file.
package require do_x3dna
set trajectories {traj-1.dcd traj-2.dcd}
do_x3dna -tp example.psf -refFrame example.pdb -trajs $trajectories -dnaAtoms "nucleic" -fitAtoms "name P"
# Uncomment it when using as script
# quit
Above example can be run through a script.
vmd -dispdev text -e run_script.tcl
Note
We recommend to use do_x3dna plugin through script with VMD as shown above.
-dispdev text
execute VMD in text mode as command and does not open
Display window.
Execute following command to get full help
package require do_x3dna
do_x3dna -help
Usage
Note
Before running do_x3dna, make sure 3DNA package is correctly working for
the input DNA/RNA structure. To check it, run do_x3dna with only reference frame
instead of trajectory file.
-noisy
option switch-on the output message from the 3DNA package on the display
that would be necessary to troubleshoot problems related to the 3DNA package
Most common problem is the residue names mismatch in input DNA/RNA structure
and the 3DNA package dictionary.
Note
Only PBC corrected trajectory files should be used as inputs.
Note
If -fitAtoms
is provided, this atoms group is used to superimpose current
frame on reference frame. Most of the parameters are unaffected by this fitting, however
coordinates of the local helical axis could mismatch with the input coordinates with the
DNA/RNA.
Note
By default, bigdcd
routine is used because it enables the trajectory reading frame by frame and allows to use
very large trajectory. It can be switched-off by using -loadAll
option.
Summary
do_x3dna -help -tp <file> -ftp <file type>
-dnaAtoms <DNA atoms> -fitAtoms <Atoms to fit>
-refFrame <Reference file> -refFrameType <reference file type>
-trajs <List of trajectory files> -trajType <trajectory file type>
-suffix <output suffix> -dt <time-step ps>
-noisy -loadAll
OPTIONS
-help
Optional
Show help and exit.
-tp
Required
Topology-Parameter file with or without coordinates (psf/prmtop/pdb/gro).
If it is pdb/gro containing coordinates of atoms, this will be used as
reference frame for fitting and base-pair calculation. In case of coordinate
files such as pdb/gro, -refFrame
will be only considered as an additional
frame as a part of trajectory.
-ftp
Optional
File format of Topology-Parameter file. If not provided, file format is automatically determined by VMD using extension.
-dnaAtoms
Optional
Atoms belonging to DNA/RNA. If not provided, by default "nucleic"
is
used to select atoms.
-fitAtoms
Optional
Atoms for fitting to reference frame. If not provided, fitting will be not done.
-refFrame
Required/Optional
Reference coordinate file for fitting and base-pair calculation. In case of psf and prmtop file, this is required because these files do not contain coordinates.
-refFrameType
Optional
File format of Reference frame file. If not provided, file format is automatically determined by VMD using extension.
-trajs
Optional
List of trajectory files. If not provided, only first frame will be used
for calculation. It is useful to check whether 3DNA is working correctly
with -noisy
option.
-trajType
Optional
File format of trajectory file. If not provided, file format is automatically determined by VMD using extension.
-suffix
Optional
Suffix for all output file names. If not provided, "g"
is used by default.
-dt
Optional
Time-step between frames in ps. It is dumped in output files and make easier for plotting. If not provided, by default, its value is 1 ps.
-noisy
Optional
Display messages and errors from 3DNA programs find_pair
and analyze
.
-loadAll
Optional
With this option, at first all trajectory will be loaded and then 3DNA will be executed for each frame. Therefore, large memory will be consumed for large trajectory.
Output Files
Following files are generated from do_x3dna
:
File name |
Output contents |
---|---|
base_pairs_g.dat |
Base-pairs |
h-bond_g.dat |
Hydrogen bonds between base-pairs |
L-BP_g.dat |
Base-pairs parameters |
L-BPS_g.dat |
Base-steps parameters |
L-BPH_g.dat |
Helical Base-steps parameters |
HelAxis_g.dat |
Local helical axis coordinates |
MGroove_g.dat |
Major and Minor grooves |
HelixRad_g.dat |
Local helical radius |
BackBoneCHiDihedrals_g.dat |
Backbone dihederal angles including Chi-dihedral |
SugarDihedrals_g.dat |
Sugar dihedral angles including puckering type |
Name of these files could be change by setting different suffix instead of g
using -suffix
option. These
files could be used with the dnaMD
module and tools for further analysis.