2021 Denovo tutorial 4 with PDBID 1EFY
Contents
Introduction
This tutorial is the second in a series of DOCK tutorials. For part I, please click here. De novo design, in practice, consists of two steps: (1) fragment library generation and (2) de novo construction. DOCK directs ligand assembly in an iterative manner; structures are grown layer by layer as DOCK samples different fragments from the sidechain, linker, and scaffold libraries.
Fragment library generation
Fragments are the basic unit of a molecule (in DOCK, that is). In general, fragments will not contain any rotatable bonds, and are treated as rigid units. The general workflow for fragment library generation proceeds in the following manner: Break the molecule(s) in the input file at each rotatable bond and insert dummy atoms at the point of cleavage. Classify the resulting fragments as sidechains (which have one dummy atom), linkers (which have 2 dummy atoms), or scaffolds (which have three or more dummy atoms).
Directory Setup
Before we begin building our libraries, we should setup our directory structure:
mkdir fraglib dn_focus dn_focus_rescore dn_generic
Focused De Novo Design
Fragment Libraries
In the first part of the tutorial, we will be building a library of fragments out of our original ligand, the benzimidazol inhibitor. Enter the fraglib directory
cd fragllib
Now create a new input file called fraglib.in. This file will be used for generating fragments.
touch fraglib.in
Now interactively run the file in DOCK6:
dock6 -i fraglib.in -o fraglib.out
conformer_search_type flex write_fragment_libraries yes fragment_library_prefix fraglib fragment_library_freq_cutoff 1 fragment_library_sort_method freq fragment_library_trans_origin no use_internal_energy yes internal_energy_rep_exp 12 internal_energy_cutoff 100.0 ligand_atom_file 1EFY_lig_with_H.mol2 limit_max_ligands no skip_molecule no read_mol_solvation no calculate_rmsd no use_database_filter no orient_ligand yes automated_matching yes receptor_site_file selected_spheres.sph max_orientations 1000 critical_points no chemical_matching no use_ligand_spheres no bump_filter no score_molecules no atom_model all vdw_defn_file /gpfs/projects/AMS536/zzz.programs/dock6.9_release/parameters/vdw_AMBER_parm99.defn flex_defn_file /gpfs/projects/AMS536/zzz.programs/dock6.9_release/parameters/flex.defn flex_drive_file /gpfs/projects/AMS536/zzz.programs/dock6.9_release/parameters/flex_drive.tbl ligand_outfile_prefix fraglib.out write_orientations no num_scored_conformers 1 rank_ligands no
The following files should have been generated:
fraglib_linker.mol2, fraglib_rigid.mol2, fraglib_scaffold.mol2, fraglib_sidechain.mol2, fraglib_torenv.dat, fraglib.out_scored.mol2
Focused De Novo Growth
Next we will be performing the second step of the de novo process: growth. Change into the dn_focus directory.
cd dn_focus
Create an input file for DOCK:
touch focus.in
Run DOCK interactively:
dock6 -i focus.in -o dn_focus.out conformer_search_type denovo dn_fraglib_scaffold_file ../fraglib/fraglib_scaffold.mol2 dn_fraglib_linker_file ../fraglib/fraglib_linker.mol2 dn_fraglib_sidechain_file ../fraglib/fraglib_sidechain.mol2 dn_user_specified_anchor no dn_use_torenv_table yes dn_torenv_table ../fraglib/fraglib_torenv.dat dn_sampling_method graph dn_graph_max_picks 30 dn_graph_breadth 3 dn_graph_depth 2 dn_graph_temperature 100.0 dn_pruning_conformer_score_cutoff 100.0 dn_pruning_conformer_score_scaling_factor 1.0 dn_pruning_clustering_cutoff 100.0 dn_constraint_mol_wt 550.0 dn_constraint_rot_bon 15 dn_constraint_formal_charge 2.0 dn_heur_unmatched_num 1 dn_heur_matched_rmsd 2.0 dn_unique_anchors 1 dn_max_grow_layers 9 dn_max_root_size 25 dn_max_layer_size 25 dn_max_current_aps 5 dn_max_scaffolds_per_layer 1 dn_write_checkpoints yes dn_write_prune_dump no dn_write_orients no dn_write_growth_trees no dn_output_prefix dn_focus.out use_internal_energy yes internal_energy_rep_exp 12 internal_energy_cutoff 100.0 use_database_filter no orient_ligand yes automated_matching yes receptor_site_file ../fraglib/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 ../../../1EFY/003.gridbox/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 /gpfs/projects/AMS536/zzz.programs/dock6.9_release/parameters/vdw_AMBER_parm99.defn flex_defn_file /gpfs/projects/AMS536/zzz.programs/dock6.9_release/parameters/flex.defn flex_drive_file /gpfs/projects/AMS536/zzz.programs/dock6.9_release/parameters/flex_drive.tbl
