2017 DOCK tutorial 1 with PDB 4QMZ NEW

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For additional Rizzo Lab tutorials see DOCK Tutorials. Use this link Wiki Formatting as a reference for editing the wiki. This tutorial was developed collaboratively by a subsection of the AMS 536 class of 2017, using DOCK v6.8.

I. Introduction

DOCK

DOCK is a molecular docking program used in drug discovery. It was developed by Irwin D. Kuntz, Jr. and colleagues at UCSF (see UCSF DOCK). This program, given a protein binding site and a small molecule, tries to predict the correct binding mode of the small molecule in the binding site, and the associated binding energy. Small molecules with highly favorable binding energies could be new drug leads. This makes DOCK a valuable drug discovery tool. DOCK is typically used to screen massive libraries of millions of compounds against a protein to isolate potential drug leads. These leads are then further studied, and could eventually result in a new, marketable drug. DOCK works well as a screening procedure for generating leads, but is not currently as useful for optimization of those leads.

DOCK 6 uses an incremental construction algorithm called anchor and grow. It is described by a three-step process:

  1. Rigid portion of ligand (anchor) is docked by geometric methods.
  2. Non-rigid segments added in layers; energy minimized.
  3. The resulting configurations are 'pruned' and energy re-minimized, yielding the docked configurations.

4QMZ

In this tutorial we will use PDB code 4QMZ, the deposited crystal structure of MST3 in complex with SUNITINIB.

Organizing Directories

While performing docking, it is convenient to adopt a standard directory structure / naming scheme, so that files are easy to find / identify.For this tutorial, we will use something similar to the following:

~username/AMS536-Spring2016/dock-tutorial/00.files/
                                         /01.dockprep/
                                         /02.surface-spheres/
                                         /03.box-grid/
                                         /04.dock/
                                         /05.large-virtual-screen/
                                         /06.virtual-screen/
                                         /07.footprint/
                                         /08.print_fps

In addition, most of the important files that are derived from the original crystal structure will be given a prefix that is the same as the PDB code, '4QMZ'. The following sections in this tutorial will adhere to this directory structure/naming scheme.

II. Preparing the Receptor and Ligand

Download the PDB file (4QMZ)

4QMZ was moved into 00.files

4qmz.pdb was copied to raw_4qmz.pdb

raw_4qmz.pdb was opened with VI terminal editor

    The header information, connect records, ions (atoms 2333 and 2334) and waters were deleted
    Res 178 = TPO, or phosphonothreonine
    Res 178 (TPO) was renamed to THR (Threonine) and HETATM renamed to ATOM, in addition the acanonical atoms were removed from the pdb leaving a deprotonated threonine (Atoms 1311-1314 in 4qmz.pdb)
    Res B49 was renamed to LIG and made Chain B

raw_4qmz.pdb was copied twice to 4qmz_rec.pdb and 4qmz_lig.pdb

4qmz_rec.pdb was opened with VI terminal editor

    LIG atoms, or chain B, was deleted and the file saved

4qmz_lig.pdb was opened with VI terminal editor

    Protein atoms, or chain A, was deleted and the file saved

4qmz_rec.pdb was loaded into tleap as a quality control measure

    tleap
    source leaprc.protein.ff14SB
    lin = loadpdb /path/to/4qmz_rec.pdb
         2340 Hydrogens added, 1 heavy atom added (CSER RES 299, Chain A, OXT 12) 
    check lin
    saveamberparm lin /path/to/4qmz_rec_leap.parm7 /path/to/4qmz_rec_leap.crd
    

Running the receptor through leap ensures a reasonable starting structure and can help identify obvious issues sooner rather than later.

At this point the .parm7 and .crd have been created via tleap ambpdb can be used to obtain the clean pdb 4qmz_rec_leap.pdb

    ambpdb -p 4qmz_rec_leap.parm7 -c 4qmz_rec_leap.crd > 4qmz_rec_leap.pdb

Now add partial charges to the receptor and save file in .mol2 format:

    open chimera
    load 4qmz_rec_leap.pdb
    Tools --> Structure editing --> Add charge --> AMBER ff99SB with AM1-BCC charges 
    File --> Save Mol2... --> 4qmz.rec.mol2 

A no-hydrogen receptor pdb file will now be created:

    Chimera, load 4qmz.rec.mol2
    Select --> Chemistry --> element --> H
    Actions --> Atoms --> Delete
    File --> Save PDB... --> 4qmz.rec.noH.pdb

Ligand (4qmz_lig.pdb) will now be charged and saved in mol2 format

    open chimera
    load 4qmz_lig.pdb
    Tools --> structure editing --> AddH
    Tools --> Structure editing --> Add charge --> AMBER ff99SB with AM1-BCC charges 
    File --> Save mol2 --> 4qmz.lig.mol2

Placement of partial charges can be verified by examining the saved files 4qmz.lig.mol2 and 4qmz.rec.mol2.

III. Generating Receptor Surface and Spheres

Open 4qmz.rec.noH.pdb in Chimera

To generate the molecular surface:

  Action --> Surface --> Show


Save the .dms file

  Tools --> Structure editing --> write DMS

.dms save to 4qmz.rec.noH.dms



Create surface spheres

create input file INSPH

    4qmz.rec.noH.dms     
    R
    X
    0.0
    4.0
    1.4
    4qmz.rec.sph

line 1 designates input file line 2 designates the generated spheres will be outside the receptor surface line 3 designates that all points on the receptor will be used line 4 designates the maximum surface radius of the spheres line 5 designates the minimum surface radius of the spheres line 6 designates the output file name

run sphgen

    sphgen -i INSPH -o OUTSPH
   

sphgen is the sphere generation program from dock -i desginates the input file: INSPH -o designates the output file

At this point it is beneficial to visualize the spheres that were created. This can be done with chimera: Open chimera from the terminal choose file --> open 4qmz.rec.mol2 choose file --> open 4qmz.rec.sph

The image that appears should resemble this:

4qmz receptor with all spheres


Then we need to select the spheres pertinent to our docking experiment. Usually these spheres will be the closest N spheres to the native ligand molecule.

Run

    sphere_selector 4qmz.rec.sph ../01.dockprep/4qmz.lig.mol2 10.0

This command will select all of the spheres within 10.0 angstroms of the ligand and output them to selected_spheres.sph

To visualize the spheres using Chimera as previously done: Launch Chimera, choose File -> Open, choose 4qmz.rec.noH.pdb File -> Open, choose output_spheres_selected.pdb Select -> Residue -> SPH Actions -> Atoms/Bonds -> sphere The selected spheres with the receptor surface should look similar to that as seen below:

4qmz receptor surface with the selected spheres within 10.0 Angstroms

IV. Generating Box and Grid

enter directory 03.box-grid

create input showbox.in

    Y
    8.0
    ../02.surface-spheres/selected_spheres.sph
    1
    4qmz.box.pdb

This input designates to dock that: we want to create a box the box length should be 8.0 Angstroms use the selected spheres in the file desginated output the box to the file specified


to use this input type:

    showbox < showbox.in

This box can be visualized in chimera using a similar approach as visualizing the spheres


Compute the energy grid

create grid.in file

    vi grid.in

grid.in needs to contain:

  compute_grids yes
  grid_spacing 0.4
  output_molecule no
  contact_score no
  energy_score yes
  energy_cutoff_distance 9999
  atom_model a
  attractive_exponent 6
  repulsive_exponent 12
  distance_dielectric yes
  dielectric_factor              4
  bump_filter yes
  bump_overlap 0.75
  receptor_file ../01.dockprep/4qmz.rec.mol2
  box_file ../03.box-grid/4qmz.box.pdb
  vdw_definition_file /opt/AMS536/dock6/parameters/vdw_AMBER_parm99.defn
  score_grid_prefix grid 


this script should output verbosely to the terminal and produce 2 output files, grid.bmp and grid.nrg, both binary files.

  grid -i grid.in > gridinfo.out

Check the standard output file gridinfo.out to ensure that individual charges on charged residues are integer values (-1 or +1).

  University of California at San Francisco, DOCK 4.0.1
  
  __________________Job_Information_________________
  launch_time                    Wed Feb  8 17:05:50 2017
  host_name                      unknown
  memory_limit                   -1
  working_directory              /home/campus.stonybrook.edu/ronassar/MySBFiles/projects/dock_tutorial/03.box-grid2_savegridoutput
  user_name                      ronassar
  
  ________________General_Parameters________________
  compute_grids                  yes
  grid_spacing                   0.4
  output_molecule                no
  
  ________________Scoring_Parameters________________
  contact_score                  no
  energy_score                   yes
  energy_cutoff_distance         9999
  atom_model                     a
  attractive_exponent            6
  repulsive_exponent             12
  distance_dielectric            yes
  dielectric_factor              4
  bump_filter                    yes
  bump_overlap                   0.75
  
  ____________________File_Input____________________
  receptor_file                  ../01.dockprep/4qmz.rec.mol2
  box_file                       ../03.box-grid/4qmz.box.pdb
  vdw_definition_file            /opt/AMS536/dock6/parameters/vdw_AMBER_parm99.defn
  
  ____________________File_Output___________________
  score_grid_prefix              grid
  
  
  
  Reading in coordinates of receptor.
  CHARGED RESIDUE MET                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE ARG                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE ARG                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE ARG                     :    1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE ARG                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE ARG                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE ARG                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE ARG                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE ASP                     :   -1.000
  CHARGED RESIDUE ARG                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE ARG                     :    1.000
  CHARGED RESIDUE LYS                     :    1.000
  CHARGED RESIDUE GLU                     :   -1.000
  CHARGED RESIDUE SER                     :   -1.000
  
  Total charge on 4qmz_rec_leap.pdb       :   -5.000
  
  Reading in grid box information.
  Box center of mass                      :   -1.912    0.054   14.111
  Box dimensions                          :   39.856   41.687   38.838
  Number of grid points per side [x y z]  :      101      106       99
  Total number of grid points             :  1059894
  
  Generating scoring grids.
  Percent of protein atoms processed      :        0
  Percent of protein atoms processed      :       10
  Percent of protein atoms processed      :       20
  Percent of protein atoms processed      :       30
  Percent of protein atoms processed      :       40
  Percent of protein atoms processed      :       50
  Percent of protein atoms processed      :       60
  Percent of protein atoms processed      :       70
  Percent of protein atoms processed      :       80
  Percent of protein atoms processed      :       90
  Percent of protein atoms processed      :      100
  Writing general grid info to grid.bmp
  Writing bump grid to grid.bmp
  Writing energy grids to grid.nrg
    Writing attractive VDW energy grid
    Writing repulsive VDW energy grid
    Writing electrostatic energy grid
  
  Finished calculation.

V. Docking a Single Molecule for Pose Reproduction

Create or enter directory 4, 04.dock

Minimization

create min.in

 vi min.in
     or
 touch min.in

min.in should contain:

  conformer_search_type                                        rigid
  use_internal_energy                                          yes
  internal_energy_rep_exp                                      12
  internal_energy_cutoff                                       100.0
  ligand_atom_file                                             ../01.dockprep/4qmz.lig.mol2
  limit_max_ligands                                            no
  skip_molecule                                                no
  read_mol_solvation                                           no
  calculate_rmsd                                               yes
  use_rmsd_reference_mol                                       yes
  rmsd_reference_filename                                      ../01.dockprep/4qmz.lig.mol2
  use_database_filter                                          no
  orient_ligand                                                no
  bump_filter                                                  no
  score_molecules                                              yes
  contact_score_primary                                        no
  contact_score_secondary                                      no
  grid_score_primary                                           yes
  grid_score_secondary                                         no
  grid_score_rep_rad_scale                                     1
  grid_score_vdw_scale                                         1
  grid_score_es_scale                                          1
  grid_score_grid_prefix                                       ../03.box-grid/grid
  multigrid_score_secondary                                    no
  dock3.5_score_secondary                                      no
  continuous_score_secondary                                   no
  footprint_similarity_score_secondary                         no
  pharmacophore_score_secondary                                no
  descriptor_score_secondary                                   no
  gbsa_zou_score_secondary                                     no
  gbsa_hawkins_score_secondary                                 no
  SASA_score_secondary                                         no
  amber_score_secondary                                        no
  minimize_ligand                                              yes
  simplex_max_iterations                                       1000
  simplex_tors_premin_iterations                               0
  simplex_max_cycles                                           1
  simplex_score_converge                                       0.1
  simplex_cycle_converge                                       1.0
  simplex_trans_step                                           1.0
  simplex_rot_step                                             0.1
  simplex_tors_step                                            10.0
  simplex_random_seed                                          0
  simplex_restraint_min                                        yes
  simplex_coefficient_restraint                                10.0
  atom_model                                                   all
  vdw_defn_file                                                /opt/AMS536/dock6/parameters/vdw_AMBER_parm99.defn
  flex_defn_file                                               /opt/AMS536/dock6/parameters/flex.defn
  flex_drive_file                                              /opt/AMS536/dock6/parameters/flex_drive.tbl
  ligand_outfile_prefix                                        4qmz.lig.min
  write_orientations                                           no
  num_scored_conformers                                        1
  rank_ligands                                                 no

run:

  dock6 -i min.in

this command will output 4qmz.lig.min_scored.mol2

This structure can be visualized using chimera and loading the surface into chimera along with the minimized and unminimized ligand structures:

4qmz with ligand before and after minimization

The RMSD of the minimized ligand to crystal structure ligand is 0.297 A.


At this point we are going to calculate the van der waals and electrostatic footprints for the unminimized and minimized ligand structures in relation to the receptor active site.

create the input file: footprint.in

  conformer_search_type                                        rigid
  use_internal_energy                                          no
  ligand_atom_file                                             ./4qmz.lig.min_scored.mol2
  limit_max_ligands                                            no
  skip_molecule                                                no
  read_mol_solvation                                           no
  calculate_rmsd                                               no
  use_database_filter                                          no
  orient_ligand                                                no
  bump_filter                                                  no
  score_molecules                                              yes
  contact_score_primary                                        no
  contact_score_secondary                                      no
  grid_score_primary                                           no
  grid_score_secondary                                         no
  multigrid_score_primary                                      no
  multigrid_score_secondary                                    no
  dock3.5_score_primary                                        no
  dock3.5_score_secondary                                      no
  continuous_score_primary                                     no
  continuous_score_secondary                                   no
  footprint_similarity_score_primary                           yes
  footprint_similarity_score_secondary                         no
  fps_use_footprint_reference_mol2                             yes
  fps_footprint_reference_mol2_filename                        ../01.dockprep/4qmz.lig.mol2
  fps_foot_compare_type                                        Euclidean
  fps_normalize_foot                                           no
  fps_foot_comp_all_residue                                    yes
  fps_receptor_filename                                        ../01.dockprep/4qmz.rec.mol2
  fps_vdw_att_exp                                              6
  fps_vdw_rep_exp                                              12
  fps_vdw_rep_rad_scale                                        1
  fps_use_distance_dependent_dielectric                        yes
  fps_dielectric                                               4.0
  fps_vdw_fp_scale                                             1
  fps_es_fp_scale                                              1
  fps_hb_fp_scale                                              0
  pharmacophore_score_secondary                                no
  descriptor_score_secondary                                   no
  gbsa_zou_score_secondary                                     no
  gbsa_hawkins_score_secondary                                 no
  SASA_score_secondary                                         no
  amber_score_secondary                                        no
  minimize_ligand                                              no
  atom_model                                                   all
  vdw_defn_file                                                /opt/AMS536/dock6/parameters/vdw_AMBER_parm99.defn
  flex_defn_file                                               /opt/AMS536/dock6/parameters/flex.defn
  flex_drive_file                                              /opt/AMS536/dock6/parameters/flex_drive.tbl
  ligand_outfile_prefix                                        fps.min.output
  write_footprints                                             yes
  write_hbonds                                                 yes
  write_orientations                                           no
  num_scored_conformers                                        1
  rank_ligands                                                 no


this footprint calculation can be run in the same way as the minimization:

  dock6 -i footprint.in

This will output three files: fps.min.output_scored.mol2

                             fps.min.output_scored_footprint_scored.txt
                             fps.min.output_hbond_scored.txt

With an in house script, plot_footprint_single_magnitude.py the two sets of footprints will be plotted for comparison

this script will be run using:

  python plot_footprint_single_magnitude.py fps.min.output_scored_footprint_scored.txt 50

The output will look something like this:

Footprint comparison between unminimized and minimized ligand structure

Notice the vdW clashes are now reduced (vdW positive peaks disappeared).


Rigid Docking

To help identify any errors in preparing the ligand and receptor files, a rigid docking, fixed growth docking and flexible docking runs will be performed. This is a check that the program can put the ligand into the crystal structure pose before proceeding.

Create an input file 'rigid.in' for the rigid docking run with the following parameters:

  conformer_search_type                                        rigid
  use_internal_energy                                          yes
  internal_energy_rep_exp                                      12
  internal_energy_cutoff                                       100.0
  ligand_atom_file                                             ../01.dockprep/4qmz.lig.mol2
  limit_max_ligands                                            no
  skip_molecule                                                no
  read_mol_solvation                                           no
  calculate_rmsd                                               yes
  use_rmsd_reference_mol                                       yes
  rmsd_reference_filename                                      ../01.dockprep/4qmz.lig.mol2
  use_database_filter                                          no
  orient_ligand                                                yes
  automated_matching                                           yes
  receptor_site_file                                           ../02.surface-spheres/selected_spheres.sph
  max_orientations                                             1000
  critical_points                                              no
  chemical_matching                                            no
  use_ligand_spheres                                           no
  bump_filter                                                  no
  score_molecules                                              yes
  contact_score_primary                                        no
  contact_score_secondary                                      no
  grid_score_primary                                           yes
  grid_score_secondary                                         no
  grid_score_rep_rad_scale                                     1
  grid_score_vdw_scale                                         1
  grid_score_es_scale                                          1
  grid_score_grid_prefix                                       ../03.box-grid/grid
  multigrid_score_secondary                                    no
  dock3.5_score_secondary                                      no
  continuous_score_secondary                                   no
  footprint_similarity_score_secondary                         no
  pharmacophore_score_secondary                                no
  descriptor_score_secondary                                   no
  gbsa_zou_score_secondary                                     no
  gbsa_hawkins_score_secondary                                 no
  SASA_score_secondary                                         no
  amber_score_secondary                                        no
  minimize_ligand                                              yes
  simplex_max_iterations                                       1000
  simplex_tors_premin_iterations                               0
  simplex_max_cycles                                           1
  simplex_score_converge                                       0.1
  simplex_cycle_converge                                       1.0
  simplex_trans_step                                           1.0
  simplex_rot_step                                             0.1
  simplex_tors_step                                            10.0
  simplex_random_seed                                          0
  simplex_restraint_min                                        no
  atom_model                                                   all
  vdw_defn_file                                                /opt/AMS536/dock6/parameters/vdw_AMBER_parm99.defn
  flex_defn_file                                               /opt/AMS536/dock6/parameters/flex.defn
  flex_drive_file                                              /opt/AMS536/dock6/parameters/flex_drive.tbl
  ligand_outfile_prefix                                        4qmz.rigid_norestraint
  write_orientations                                           no
  num_scored_conformers                                        50
  write_conformations                                          no
  cluster_conformations                                        yes
  cluster_rmsd_threshold                                       2.0
  rank_ligands                                                 no

Outputs the file "4qmz.rigid_norestraint" the no restraint refers to the option of the parameter simplex_restraint_min in the input file. This removes the tether when doing the minimization. The best scoring structure had an RMSD of 1.??? to the native ligand pose.

Rigid docking results

Fixed Anchor Docking

In fixed anchor docking, the ligand location is fixed in the active site and the rotatable bonds space is searched (i.e angles are flexible).

Create an input file 'fad.in' for the rigid docking run with the following parameters: Notice the search algorithm is now rigidset to flex (for flexible) and orient option is set to no (for fixing the anchor in place).

  conformer_search_type                                        flex
  user_specified_anchor                                        no
  limit_max_anchors                                            no
  min_anchor_size                                              5
  pruning_use_clustering                                       yes
  pruning_max_orients                                          1000
  pruning_clustering_cutoff                                    100
  pruning_conformer_score_cutoff                               100.0
  pruning_conformer_score_scaling_factor                       1.0
  use_clash_overlap                                            no
  write_growth_tree                                            no
  use_internal_energy                                          yes
  internal_energy_rep_exp                                      12
  internal_energy_cutoff                                       100.0
  ligand_atom_file                                             ../01.dockprep/4qmz.lig.mol2
  limit_max_ligands                                            no
  skip_molecule                                                no
  read_mol_solvation                                           no
  calculate_rmsd                                               yes
  use_rmsd_reference_mol                                       yes
  rmsd_reference_filename                                      ../01.dockprep/4qmz.lig.mol2
  use_database_filter                                          no
  orient_ligand                                                no
  automated_matching                                           yes
  receptor_site_file                                           ../02.surface-spheres/selected_spheres.sph
  max_orientations                                             1000
  critical_points                                              no
  chemical_matching                                            no
  use_ligand_spheres                                           no
  bump_filter                                                  no
  score_molecules                                              yes
  contact_score_primary                                        no
  contact_score_secondary                                      no
  grid_score_primary                                           yes
  grid_score_secondary                                         no
  grid_score_rep_rad_scale                                     1
  grid_score_vdw_scale                                         1
  grid_score_es_scale                                          1
  grid_score_grid_prefix                                       ../03.box-grid/grid
  multigrid_score_secondary                                    no
  dock3.5_score_secondary                                      no
  continuous_score_secondary                                   no
  footprint_similarity_score_secondary                         no
  pharmacophore_score_secondary                                no
  descriptor_score_secondary                                   no
  gbsa_zou_score_secondary                                     no
  gbsa_hawkins_score_secondary                                 no
  SASA_score_secondary                                         no
  amber_score_secondary                                        no
  minimize_ligand                                              yes
  minimize_anchor                                              yes
  minimize_flexible_growth                                     yes
  use_advanced_simplex_parameters                              no
  simplex_max_cycles                                           1
  simplex_score_converge                                       0.1
  simplex_cycle_converge                                       1.0
  simplex_trans_step                                           1.0
  simplex_rot_step                                             0.1
  simplex_tors_step                                            10.0
  simplex_anchor_max_iterations                                500
  simplex_grow_max_iterations                                  500
  simplex_grow_tors_premin_iterations                          0
  simplex_random_seed                                          0
  simplex_restraint_min                                        no
  atom_model                                                   all
  vdw_defn_file                                                /opt/AMS536/dock6/parameters/vdw_AMBER_parm99.defn
  flex_defn_file                                               /opt/AMS536/dock6/parameters/flex.defn
  flex_drive_file                                              /opt/AMS536/dock6/parameters/flex_drive.tbl
  ligand_outfile_prefix                                        4qmz.fad
  write_orientations                                           no
  num_scored_conformers                                        100
  write_conformations                                          no
  cluster_conformations                                        yes
  cluster_rmsd_threshold                                       2.0
  rank_ligands                                                 no
Fixed anchor docking results

Flexible Docking

In flexible docking, the ligand location and rotatable bonds are search.

Create an input file 'flex.in' for the flexible docking run with the following parameters: Notice the search algorithm is now set to flex (for flexible) and orient option is set to yes (for fixing the anchor in place).

  conformer_search_type                                        flex
  user_specified_anchor                                        no
  limit_max_anchors                                            no
  min_anchor_size                                              5
  pruning_use_clustering                                       yes
  pruning_max_orients                                          1000
  pruning_clustering_cutoff                                    100
  pruning_conformer_score_cutoff                               100.0
  pruning_conformer_score_scaling_factor                       1.0
  use_clash_overlap                                            no
  write_growth_tree                                            no
  use_internal_energy                                          yes
  internal_energy_rep_exp                                      12
  internal_energy_cutoff                                       100.0
  ligand_atom_file                                             ../01.dockprep/4qmz.lig.mol2
  limit_max_ligands                                            no
  skip_molecule                                                no
  read_mol_solvation                                           no
  calculate_rmsd                                               yes
  use_rmsd_reference_mol                                       yes
  rmsd_reference_filename                                      ../01.dockprep/4qmz.lig.mol2
  use_database_filter                                          no
  orient_ligand                                                yes
  automated_matching                                           yes
  receptor_site_file                                           ../02.surface-spheres/selected_spheres.sph
  max_orientations                                             1000
  critical_points                                              no
  chemical_matching                                            no
  use_ligand_spheres                                           no
  bump_filter                                                  no
  score_molecules                                              yes
  contact_score_primary                                        no
  contact_score_secondary                                      no
  grid_score_primary                                           yes
  grid_score_secondary                                         no
  grid_score_rep_rad_scale                                     1
  grid_score_vdw_scale                                         1
  grid_score_es_scale                                          1
  grid_score_grid_prefix                                       ../03.box-grid/grid
  multigrid_score_secondary                                    no
  dock3.5_score_secondary                                      no
  continuous_score_secondary                                   no
  footprint_similarity_score_secondary                         no
  pharmacophore_score_secondary                                no
  descriptor_score_secondary                                   no
  gbsa_zou_score_secondary                                     no
  gbsa_hawkins_score_secondary                                 no
  SASA_score_secondary                                         no
  amber_score_secondary                                        no
  minimize_ligand                                              yes
  minimize_anchor                                              yes
  minimize_flexible_growth                                     yes
  use_advanced_simplex_parameters                              no
  simplex_max_cycles                                           1
  simplex_score_converge                                       0.1
  simplex_cycle_converge                                       1.0
  simplex_trans_step                                           1.0
  simplex_rot_step                                             0.1
  simplex_tors_step                                            10.0
  simplex_anchor_max_iterations                                500
  simplex_grow_max_iterations                                  500
  simplex_grow_tors_premin_iterations                          0
  simplex_random_seed                                          0
  simplex_restraint_min                                        no
  atom_model                                                   all
  vdw_defn_file                                                /opt/AMS536/dock6/parameters/vdw_AMBER_parm99.defn
  flex_defn_file                                               /opt/AMS536/dock6/parameters/flex.defn
  flex_drive_file                                              /opt/AMS536/dock6/parameters/flex_drive.tbl
  ligand_outfile_prefix                                        4qmz.flex
  write_orientations                                           no
  num_scored_conformers                                        100
  write_conformations                                          no
  cluster_conformations                                        yes
  cluster_rmsd_threshold                                       2.0
  rank_ligands                                                 no
Flexible docking results

VI. Virtual Screening

VIII. Frequently Encountered Problems