Multi-Conformation Docking: Enhanced Conformational Sampling and Multi-Stage Docking for Improved Docking Accuracy
Author: Hang Zheng
Create Time:2023-12-06
License:BY-NC-SA 4.0
Introduction
Traditional molecular docking methods typically involve positioning the ligand molecule within the binding pocket of the target protein and then sampling its rotations, translations, and torsions of rotatable bonds to identify the optimal binding pose. However, due to computational resource constraints and the vast search space resulting from 3D continuity, these methods often assess only a subset of possible conformational combinations. Consequently, this can lead to suboptimal docking results in some protein-ligand complex systems.
Multi-Conformation Docking (mcdock) addresses this limitation by advancing the conformational search process into the molecule preparation phase, thereby artificially ensuring a more comprehensive coverage of the search space in an attempt to enhance the reliability of molecular docking. It consists of three steps: optional Conformation Generation, Rigid Docking, and Local Refinement.
Advantages of MultiConfDock
Comprehensive Conformation Generation:
confgen
can rapidly generate a diverse array of low-energy conformations, ensuring that the search space encompasses as many ligand conformations as possible, increasing the likelihood of identifying suitable binding poses.Efficient Rigid Docking: The method is capable of swiftly evaluating a vast number of ligand conformations for their relative positions and orientations within the protein's binding pocket, ensuring a thorough coverage of the search space for each ligand conformation.
Refined Local Refinement: MultiConfDock allows for minor local movements of the ligand to fine-tune the docking pose, ensuring that each binding pose is at a locally optimized structure.
This workflow is not only efficient but also powerful in predicting the optimal protein-ligand binding complexes.
Step-by-Step Implementation of Multi-Conformation Docking
Firstly, let's check the performace of Uni-Dock on redocking task of 6X8D from PoseBuster.
PDB Code: 6X8D Min RMSD (Top 1): 3.329471638113171 Min RMSD (Top 3): 3.329471638113171 Min RMSD (Top 5): 3.329471638113171 Min RMSD (Top 10): 3.329471638113171
Step 0. Conformation Generation
This is the optional zeroth step in the MultiConfDock process. In this phase, MultiConfDock generates multiple conformations of the ligand. This is achieved using a conformation generation algorithm known as confgen
. confgen
employs CDPKit
that can efficiently generate a large number of ligand conformations. This step is optional, and if the user already has the conformations of the ligand, he can skip this step.
5 conformations are generated by ConfGen for 6X8D ligand.
Step 1. Rigid Docking
The first step in the process is RigidDock. In this phase, MultiConfDock performs a rigid docking of each ligand conformation against the target protein. This means that the ligand and the protein are treated as rigid bodies, and only their relative positions and orientations change. This step is computationally efficient and allows MultiConfDock to quickly evaluate a large number of ligand conformations.
unidock --receptor 6X8D_receptor.pdbqt --ligand_index ligand_index.txt --center_x 22.7196 --center_y -0.9656300000000002 --center_z 70.91402999999998 --size_x 13.529800000000002 --size_y 14.329699999999999 --size_z 12.241900000000001 --scoring vina --dir 6X8D_rigiddock_output --exhaustiveness 128 --max_step 20 --num_modes 3 --verbosity 2 --refine_step 5 --keep_nonpolar_H
Step 2. Local Refinement
After the RigidDock phase, MultiConfDock proceeds to the LocalRefine step. In this phase, the top scoring conformations from the RigidDock step are selected, and a local refinement is performed. This involves allowing small, local movements of the ligand and the protein to fine-tune the docking pose. This step is more computationally intensive, but it is applied only to a subset of the initial conformations, making the process efficient.
unidock --receptor 6X8D_receptor.pdbqt --ligand_index ligand_index.txt --center_x 22.7196 --center_y -0.9656300000000002 --center_z 70.91402999999998 --size_x 13.529800000000002 --size_y 14.329699999999999 --size_z 12.241900000000001 --scoring vina --dir 6X8D_localrefine_output --exhaustiveness 512 --max_step 40 --num_modes 1 --verbosity 2 --refine_step 5 --keep_nonpolar_H --local_only b''
Evaluation: Calculate the RMSD between the crystal structure and docked structure from mcdock
PDB Code: 6X8D Min RMSD (Top 1): 1.3844682036796658 Min RMSD (Top 3): 1.3844682036796658 Min RMSD (Top 5): 1.3844682036796658 Min RMSD (Top 10): 1.3844682036796658 [15:05:47] ERROR: Problems encountered parsing data fields [15:05:47] ERROR: moving to the beginning of the next molecule [15:05:47] ERROR: Problems encountered parsing data fields [15:05:47] ERROR: moving to the beginning of the next molecule [15:05:47] ERROR: Problems encountered parsing data fields [15:05:47] ERROR: moving to the beginning of the next molecule [15:05:47] ERROR: Problems encountered parsing data fields [15:05:47] ERROR: moving to the beginning of the next molecule [15:05:47] ERROR: Problems encountered parsing data fields [15:05:47] ERROR: moving to the beginning of the next molecule [15:05:47] ERROR: Problems encountered parsing data fields [15:05:47] ERROR: moving to the beginning of the next molecule [15:05:47] ERROR: Problems encountered parsing data fields [15:05:47] ERROR: moving to the beginning of the next molecule
By combining these steps, MultiConfDock can efficiently identify the optimal protein-ligand binding complexes. This makes it a powerful tool for researchers in the field of drug design.
mcdock
: An Automated Workflow for Multi-Conformation Docking
mcdock
is now open source
https://github.com/dptech-corp/Uni-Dock/tree/mcdock/unidock_tools/MultiConfDock
Installation
mcdock
is now available using Docker:
docker pull dptechnology/unidock_tools:latest
After the image is pulled, you can run a Docker container using the following command:
docker run --gpus 0 -dit --name mcdock dptechnology/unidock_tools:latest
docker attach mcdock
Usage
mcdock
is controlled via several command-line parameters:
unidocktools mcdock --help
Here's a brief overview:
Required Arguments
-r, --receptor
: Path to the receptor file in PDBQT format.-l, --ligands
: Path to the ligand file in SDF format. For multiple files, separate them by commas.-i, --ligand_index
: A text file containing the path of ligand files in sdf format.
ConfGen Arguments
-g, --gen_conf
: Whether to generate conformers for the ligands (default: False).-n, --max_num_confs_per_ligand
: Maximum number of conformers to generate for each ligand (default: 1000).-m, --min_rmsd
: Minimum RMSD for output conformer selection (default: 0.5000, must be >= 0, 0 disables RMSD checking).
Docking Box Parameters
-cx, --center_x
: X-coordinate of the docking box center.-cy, --center_y
: Y-coordinate of the docking box center.-cz, --center_z
: Z-coordinate of the docking box center.-sx, --size_x
: Width of the docking box in the X direction (default: 22.5).-sy, --size_y
: Width of the docking box in the Y direction (default: 22.5).-sz, --size_z
: Width of the docking box in the Z direction (default: 22.5).
Directory
-wd, --workdir
: Working directory (default: 'MultiConfDock').-sd, --savedir
: Save directory (default: 'MultiConfDock-Result').-bs, --batch_size
: Batch size for mcdock (default: 20).
Rigid Docking Parameters
-sf_rd, --scoring_function_rigid_docking
: Scoring function used in rigid docking (default: 'vina').-ex_rd, --exhaustiveness_rigid_docking
: exhaustiveness used in rigid docking (default: 128).-ms_rd, --maxstep_rigid_docking
: maxstep used in rigid docking (default: 20)-nm_rd, --num_modes_rigid_docking
: Number of modes used in rigid docking (default: 3).-rs_rd, --refine_step_rigid_docking
: Refine step used in rigid docking (default: 3).-topn_rd, --topn_rigid_docking
: Top N results used in rigid docking (default: 100).
Local Refine Parameters
-sf_lr, --scoring_function_local_refine
: Scoring function used in local refine (default: 'vina').-ex_lr, --exhaustiveness_local_refine
: exhaustiveness used in local refine (default: 32)-ms_lr, --maxstep_local_refine
: maxstep used in local refine (default: 40)-nm_lr, --num_modes_local_refine
: Number of modes used in local refine (default: 1).-rs_lr, --refine_step_local_refine
: Refine step used in local refine (default: 5).-topn_lr, --topn_local_refine
: Top N results used in local refine (default: 1).
These parameters allow you to control the behavior of mcdock
and customize it to suit your specific needs.
Example
unidocktools mcdock --receptor 6X8D_receptor.pdbqt --ligands 6X8D_ligand_ori.sdf --center_x 22.7196 --center_y -0.9656300000000002 --center_z 70.91402999999998 --size_x 13.529800000000002 --size_y 14.329699999999999 --size_z 12.241900000000001 --gen_conf --max_num_confs_per_ligand 200 --min_rmsd 0.3 --workdir MCDOCK_work --savedir MCDOCK_result --exhaustiveness_rigid_docking 128 --max_step_rigid_docking 20 --topn_rigid_docking 100 --num_modes_rigid_docking 3 --exhaustiveness_local_refine 512 --max_step_local_refine 40 --topn_local_refine 10 --num_modes_local_refine 1
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