# Command Line Interface Quickstart¶

This chapter provides a step-by-step introduction on how to use the SilcsBio Command Line Interface (CLI). Example commands assume a Bash shell is being used.

## SILCS simulation from the command line¶

1. Set the environment variables required to access the software:

export GMXDIR=<gromacs/bin>
export SILCSBIODIR=<silcsbio>

2. Set up the SILCS simulations:

${SILCSBIODIR}/silcs/1_setup_silcs_boxes prot=<Protein PDB>  To determine if the setup is complete check that the 10 PDB files required for the simulations are available using the command ls 1_setup/*_silcs.*.pdb 3. Submit the SILCS GCMC/MD jobs to the queue: ${SILCSBIODIR}/silcs/2a_run_gcmd prot=<Protein PDB>


This will submit 10 jobs to the queue. To check job progress, use:

${SILCSBIODIR}/silcs/check_progress  This will provide a summary list of the SILCS jobs consisting of the full job path, the job number, the task ID, the job status, and the current/total number of GCMC/MD cycles. Job status values are: Q queued, R running, E successfully completed, F failed, NA not submitted. 4. When the GCMC/MD jobs are finished, generate FragMaps: ${SILCSBIODIR}/silcs/2b_gen_maps prot=<Protein PDB>


This command will submit 10 jobs to the queue for calculating the occupancy maps from individual runs. Once they are done, use the following command to create the FragMaps:

${SILCSBIODIR}/silcs/2c_fragmap prot=<Protein PDB>  This command will create a silcs_fragmap_<Protein PDB> folder, which contains final FragMap and VMD/PyMol scripts for easy visualization: pymol view_maps.pml # PyMol vmd -e view_maps.vmd # VMD  Additional files that are created include those needed for subsequent SILCS-MC docking and the file overlap_coefficient.dat. The overlap coefficients in this file are a measure of convergence for SILCS simulations. If the coefficients are less than 0.7, you may consider extending the SILCS simulations. For visualization in MOE, 2c_fragmaps needs to be re-run with extra option. ${SILCSBIODIR}/silcs/2c_fragmap prot=<Protein PDB> cns=true


This command will create a CNS format map files and view_maps.svl script file. To visualize the maps in MOE, start MOE and open “Surfaces and Maps” panel, and type the following command in the SVL console.

run 'view_maps.svl'


For additional details, please see SILCS: Site Identification by Ligand Competitive Saturation.

## SSFEP simulation from the command line¶

1. Set the environment variables required to access the software:

export GMXDIR=<gromacs/bin>
export SILCSBIODIR=<silcsbio>

2. Set up the SSFEP simulations:

${SILCSBIODIR}/ssfep/1_setup_ssfep lig=<Ligand Mol2/SDF file> prot=<Protein PDB>  To determine if the setup is completed check that the PDB files required for the simulations are available using the command ls 1_setup/*/*_gmx_wat.pdb. The listing should show PDB files for the ligand alone and for the protein/ligand complex. 3. Submit the SSFEP MD simulation jobs to the queueing system: ${SILCSBIODIR}/ssfep/2_run_md_ssfep lig=<Ligand Mol2/SDF file> prot=<Protein PDB>


This will submit 10 jobs to the queue, 5 for the protein:ligand complex and 5 for the ligand. To check job progress, use:

${SILCSBIODIR}/ssfep/check_progress  This will provide a summary list of the SSFEP jobs consisting of the full job path, the job number, the task ID, the job status, and the current/total number of SSFEP cycles. Job status values are: Q queued, R running, E successfully completed, F failed, NA not submitted. 4. When the SSFEP MD simulation jobs are finished, use the ligand modification files to submit the $$\Delta \Delta G$$ calculations: ${SILCSBIODIR}/ssfep/3a_setup_modifications lig=<Ligand Mol2/SDF file> prot=<Protein PDB> mod=<modification file>


This command will submit 10 jobs, each of which processes one of the MD trajectories for all modifications in the modification file. Depending on the number and sizes of the modifications, this step may take minutes to several hours to complete.

Once completed, use the following command to collate the results for all of the modifications:

\${SILCSBIODIR}/ssfep/3b_calc_ddG_ssfep mod=<modification file>


This command will create a lig_decor.csv file, which contains the free energy change for each modification relative to the parent ligand. SSFEP is designed to evaluate small modifications and results are best interpreted qualitatively. Therefore it is recommended that only the sign of the change, and not the magnitude, be used to inform decision making: values < 0 indicate a modification predicted to be favorable.

For additional details, please see SSFEP: Single Step Free Energy Perturbation.