genion(1)

NAME
genion VERSION 3.2.0

SYNOPSIS
genion -s topol.tpr -table table.xvg -n index.ndx -o out.gro -g genion.log -pot pot.pdb -[no]h -nice int -np int -pname string -pq real -nn int -nname string -nq real -rmin real -[no]random -seed int -scale real

DESCRIPTION
genion replaces solvent molecules by monoatomic ions at the position of the first atoms with the most favorable electrostatic potential or at random. The potential is calculated on all atoms, using normal GROMACS particle based methods (in contrast to other methods based on solving the Poisson-Boltzmann equation). The potential is recalculated after every ion insertion. If specified in the run input file, a reaction field, shift function or user function can be used. For the user function a table file can be specified with the option -table The group of solvent molecules should be continuous and all molecules should have the same number of atoms. The user should add the ion molecules to the topology file and include the file ions.itp Ion names for Gromos96 should include the charge. With the option -pot the potential can be written as B-factors in a pdb file (for visualisation using e.g. rasmol). The unit of the potential is 1000 kJ/(mol e), the scaling be changed with the -scale option. For larger ions, e.g. sulfate we recommended to use genbox.

FILES
-s topol.tpr Input
 Generic run input: tpr tpb tpa xml -table table.xvg Input, Opt.
 xvgr/xmgr file -n index.ndx Input, Opt.
 Index file -o out.gro Output
 Generic structure: gro g96 pdb xml -g genion.log Output
 Log file -pot pot.pdb Output, Opt.
 Protein data bank file

OTHER OPTIONS
-[no]h no
 Print help info and quit -nice int 19
 Set the nicelevel -np int 0
 Number of positive ions -pname string Na
 Name of the positive ion -pq real 1
 Charge of the positive ion -nn int 0
 Number of negative ions -nname string Cl
 Name of the negative ion -nq real -1
 Charge of the negative ion -rmin real 0.6
 Minimum distance between ions -[no]random no
 Use random placement of ions instead of based on potential. The rmin option should still work -seed int 1993
 Seed for random number generator -scale real 0.001
 Scaling factor for the potential for -pot