Optional Parameters

Input Options

-dbase <filename>

Input molecules to pose-predict. 3D molecules must be input as conformational expansion is not performed prior to fitting.

-dbase is the fastest way to run POSIT on large datasets. The expected input is a pre-generated database of OMEGA generated conformers.

> omega2 -in renin/all.smi -out all.oeb.gz -rangeIncrement 1 \
   -maxConfRange 200,200,300,400,500,600,700,800,900,1000,1100,1200,1300,1400,1500,1600

> posit -receptor receptor.oedu -dbase all.oeb.gz

Supported input file formats are:

File type



.oeb .oeb.gz


.sdf .mol .sdf.gz .mol.gz


.mol2 .mol2.gz


.pdb .ent .pdb.gz .ent.gz


This flag specifies a text file with the names of one or more molecules in supplied to the -dbase flag. If specified, only molecules with matching names will be read by the -dbase flag. If this flag is not specified all molecules will be read normally. Molecules names should be listed one per line.

The general purpose of this flag is to provide an easy mechanism for reading a few specific molecules that are contained in a large database, without having to extract those molecules by hand from the database.

Multiprocessing Options

Execute Options


The argument for this flag is the name of a file containing control parameters. The control parameter file acts to either replace or augment the command line interface. All parameters necessary for program execution may be provided in the control parameter file, although any command given explicitly on the command line will supersede options found in the parameter file. The application generates a new parameter file containing the full set of execution parameters upon every execution. The name of the parameter file is created by combining the prefix base name with the ‘.param’ extension.

-mpi_np <n>

Specifies the number of processors n when the application is run in MPI mode.

-mpi_hostfile <filename>

Specifies the name of the file containing processors configuration. For every host this file should contain a line host_name slots=n where n is the number of processors on the host.

Dock Options


When examining the ligands to pose predict for stereo, ignore any missing nitrogen chirality. (This is normally caused by time averaging of crystal structures).

When expanding stereo, nitrogen stereo centers will not be assigned.


POSIT may complain about stereo centers being changed by the optimization, this is more likely when ignoring nitrogen stereo centers since the optimization may decide a different stereo configuration is optimal.

This command is aliased to -ignoreNitrogenStereo.

POSIT now always expands missing stereo.


Minimum probability for poses of interest. POSIT only outputs poses that has the minimum required probability. Poses that has a probability lower than the specified minimum are also excluded from post-prediction relaxation. To output all poses or to relax all poses, set -minimum_probability to 0.

[default = 0.33]


Clashes allowed in the generated poses. There are three levels:

Allowed Clash



No clashes are allowed. Actually there is a little wiggle room here less than 0.2 Å penetration is not considered a clash.


Clashes involving hydrogen are allowed, but


those between heavy atoms are disallowed.


All clashes are allowed.

All poses that are accepted by the probability calculation yet clash with the protein are written to the fail file (if specified).

[default = mildclashes]


Flag indicating if post pose prediction relaxation should be performed. The relaxation is performed by allowing flexibility to the ligand and parts of the receptor. Turning on relaxation can significantly slow down the calculations. There are three options:

Relax Mode



No relaxation is performed.


Relaxation is performed on poses that contains clashes.


Relaxation is performed on all poses.

[default = none]


Number of alternative poses to be generated for each docked molecule. The default is to only generate a single most probable pose.

[default = 1]


If this flag set to false the return of pose prediction result correspond to all receptors. The default setting return pose or poses corresponding to the best receptor.

[default = true]

Output File Options

POSIT writes docked structure results to a single file, -docked_molecule_file – Ligand only output in one file.

By default, not all poses may be written to the output, to see where ligands were placed, consult the log file for more details. To control this behavior use the -outputall flag, which writes all output to the file specified by -out in order of input molecule.

-docked_molecule_file <filename>

If specified, this flag overrides the default name of the docked molecule output file. Only .oedu, .oeb, and .oeb.gz formats are allowed. An .oedu file is generated by default, and is the preferred output format.


The default file is posit_docked.oedu, or <-prefix>_docked.oedu if the -prefix flag is specified.

Ligands are written to the output file based on the desired sort order (see the -sortby flag).


This command is aliased to -out.


If specified this flag overrides the default name for the undocked molecule file.


The default filename is posit_undocked.oeb.gz, or <-prefix>_undocked.oeb.gz if -prefix is specified.


If specified overrides the default name of the output text file containing the scores of the docked molecules.


The default filename is posit_score.txt or <-prefix>_score.txt if the -prefix flag is specified.


If specified overrides the default output filename for the report file.


The default filename for the report file is posit_report.txt or <-prefix>_report.txt if the -prefix flag is specified.


If specified overrides the default filename for the status file.


The default status file name is posit_status.txt or <-prefix>_status.txt if the -prefix flag is specified.


If specified overrides the default filename for the reject file.

The reject file is a tab separated file containing the input ligand number, the ligand title and the reason for the ligand being undocked.

Example output:

Ligand #        Title#Status
0       lig1    No conformers above minimum probability
1       lig2    No conformers above minimum probability
2       lig3    No conformers above minimum probability
3       lig4    No conformers above minimum probability


The default status file name is posit_rejected.txt or <-prefix>_rejected.txt if the -prefix flag is specified.


If specified overrides the default output filename for the setting file.


The default settings filename is posit_settings.param or <-prefix>_settings.param if the -prefix flag is specified.

-clashed_molecule_file <filename>

Occasionally POSIT rejects ligands that probably have the correct binding mode but also display uncorrectable clashes. If this flag is set, clashed molecules will be written to this file in no specific output order.

It is important to be aware that because these are likely binding modes there is a chance that the clashed poses are still correct but the protein has reconfigured to accept the clashed pose.


This command is aliased to -clash.

Output Options


Overrides the default tag used to attach the score to the output molecules


Suppress the default output of the score, status, settings, report and undocked files.


Suppress writing a dot (.) to standard error for each docking molecule (or x in the case of a failure).


The text passed to this parameter will be preappended to all default output filenames (it does not affect output filenames explicitly set by the users).


Shorthand to write all output including clashed or non probable molecules.