DOKK / manpages / debian 11 / gromacs-data / gmx-rmsf.1.en
GMX-RMSF(1) GROMACS GMX-RMSF(1)

gmx-rmsf - Calculate atomic fluctuations

gmx rmsf [-f [<.xtc/.trr/...>]] [-s [<.tpr/.gro/...>]] [-n [<.ndx>]]


         [-q [<.pdb>]] [-oq [<.pdb>]] [-ox [<.pdb>]] [-o [<.xvg>]]


         [-od [<.xvg>]] [-oc [<.xvg>]] [-dir [<.log>]] [-b <time>]


         [-e <time>] [-dt <time>] [-[no]w] [-xvg <enum>] [-[no]res]


         [-[no]aniso] [-[no]fit]


gmx rmsf computes the root mean square fluctuation (RMSF, i.e. standard deviation) of atomic positions in the trajectory (supplied with -f) after (optionally) fitting to a reference frame (supplied with -s).

With option -oq the RMSF values are converted to B-factor values, which are written to a .pdb file. By default, the coordinates in this output file are taken from the structure file provided with -s,although you can also use coordinates read from a different .pdb fileprovided with -q. There is very little error checking, so in this caseit is your responsibility to make sure all atoms in the structure fileand .pdb file correspond exactly to each other.

Option -ox writes the B-factors to a file with the average coordinates in the trajectory.

With the option -od the root mean square deviation with respect to the reference structure is calculated.

With the option -aniso, gmx rmsf will compute anisotropic temperature factors and then it will also output average coordinates and a .pdb file with ANISOU records (corresonding to the -oq or -ox option). Please note that the U values are orientation-dependent, so before comparison with experimental data you should verify that you fit to the experimental coordinates.

When a .pdb input file is passed to the program and the -aniso flag is set a correlation plot of the Uij will be created, if any anisotropic temperature factors are present in the .pdb file.

With option -dir the average MSF (3x3) matrix is diagonalized. This shows the directions in which the atoms fluctuate the most and the least.

Options to specify input files:

Trajectory: xtc trr cpt gro g96 pdb tng
Structure+mass(db): tpr gro g96 pdb brk ent
Index file
Protein data bank file

Options to specify output files:

Protein data bank file
Protein data bank file
xvgr/xmgr file
xvgr/xmgr file
xvgr/xmgr file
Log file

Other options:

Time of first frame to read from trajectory (default unit ps)
Time of last frame to read from trajectory (default unit ps)
Only use frame when t MOD dt = first time (default unit ps)
-[no]w (no)
View output .xvg, .xpm, .eps and .pdb files
xvg plot formatting: xmgrace, xmgr, none
-[no]res (no)
Calculate averages for each residue
-[no]aniso (no)
Compute anisotropic termperature factors
-[no]fit (yes)
Do a least squares superposition before computing RMSF. Without this you must make sure that the reference structure and the trajectory match.

gmx(1)

More information about GROMACS is available at <http://www.gromacs.org/>.

2021, GROMACS development team

March 29, 2021 2020.6-Debian-2020.6-2