gmx insert-molecules

Synopsis

gmx insert-molecules [-f [<.gro/.g96/...>]] [-ci [<.gro/.g96/...>]]
             [-ip [<.dat>]] [-o [<.gro/.g96/...>]] [-box <vector>]
             [-nmol <int>] [-try <int>] [-seed <int>]
             [-radius <real>] [-scale <real>] [-dr <vector>]
             [-rot <enum>]

Description

gmx insert-molecules inserts -nmol copies of the system specified in the -ci input file. The insertions take place either into vacant space in the solute conformation given with -f, or into an empty box given by -box. Specifying both -f and -box behaves like -f, but places a new box around the solute before insertions. Any velocities present are discarded.

By default, the insertion positions are random (with initial seed specified by -seed). The program iterates until -nmol molecules have been inserted in the box. Molecules are not inserted where the distance between any existing atom and any atom of the inserted molecule is less than the sum based on the van der Waals radii of both atoms. A database (vdwradii.dat) of van der Waals radii is read by the program, and the resulting radii scaled by -scale. If radii are not found in the database, thoseatoms are assigned the (pre-scaled) distance -radius.

A total of -nmol * -try insertion attempts are made before giving up. Increase -try if you have several small holes to fill. Option -rot specifies whether the insertion molecules are randomly oriented before insertion attempts.

Alternatively, the molecules can be inserted only at positions defined in positions.dat (-ip). That file should have 3 columns (x,y,z), that give the displacements compared to the input molecule position (-ci). Hence, if that file should contain the absolute positions, the molecule must be centered on (0,0,0) before using gmx insert-molecules (e.g. from gmx editconf -center). Comments in that file starting with # are ignored. Option -dr defines the maximally allowed displacements during insertial trials. -try and -rot work as in the default mode (see above).

Options

Options to specify input files:

-f [<.gro/.g96/…>] (protein.gro) (Optional)

Existing configuration to insert into: gro g96 pdb brk ent esp tpr

-ci [<.gro/.g96/…>] (insert.gro)

Configuration to insert: gro g96 pdb brk ent esp tpr

-ip [<.dat>] (positions.dat) (Optional)

Predefined insertion trial positions

Options to specify output files:

-o [<.gro/.g96/…>] (out.gro)

Output configuration after insertion: gro g96 pdb brk ent esp

Other options:

-box <vector> (0 0 0)

Box size (in nm)

-nmol <int> (0)

Number of extra molecules to insert

-try <int> (10)

Try inserting -nmol times -try times

-seed <int> (1997)

Random generator seed

-radius <real> (0.105)

Default van der Waals distance

-scale <real> (0.57)

Scale factor to multiply Van der Waals radii from the database in share/gromacs/top/vdwradii.dat. The default value of 0.57 yields density close to 1000 g/l for proteins in water.

-dr <vector> (0 0 0)

Allowed displacement in x/y/z from positions in -ip file

-rot <enum>

Rotate inserted molecules randomly: xyz, z, none