AutoDock4 Pose Reproduction Tutorial
The purpose of this tutorial is to provide members of the Rizzo lab a way to benchmark the AutoDock4 software to compare the Pose Reproduction success rates against the DOCK6 software. (Note: The program version used for this experiment was AutoDock4.2.6 and DOCK6.9
Contents
I. Introduction
AutoDock4 is a commonly used docking program which assess the affinity of a ligand, a drug candidate to a target site (Protein, Enzyme, RNA). To evaluate a software's ability to accurately reproduce experimental results, an experiment called Pose Reproduction was developed
Pose Reproduction used an experimental known ligand and protein complex from the PDB database and attempts to dock this ligand back into it's original location. If the lowest energy ligand(most energetically favorable) is within 2.0 RMSDh of the original target site, this is referred to as a docking success. If any of the ligands, but not the lowest energy ligand is within 2.0 RMSDh of the original target site, this is referred to as a scoring failure. If none of the ligands are within 2.0 RMSDh of the original target site this is referred to as a sampling failure.
II.Prepping Directories
First step is prepare a file with a list of systems within it. For this docking experiment this file was called clean.systems.all
121P 181L 182L 183L 184L etc
Second step run the run.000.AutoDock.source.sh script to prepare a directory for each system in the file. The 1st arguement is the list of systems file made in the previous step. The 2nd Arguement is the new directory that will be made where all the AutoDock4 experiments will be performed
bash ./run.000.AutoDock.source.sh ../clean.systems.all AutoDock4_Tutorial
The directory where all the directories will be formed is
AutoDock4_Tutorial/
Each System will have it's own directory in this file
AutoDock4_Tutorial/121P/ AutoDock4_Tutorial/181L/ AutoDock4_Tutorial/182L/ etc
III.Preparing Receptors and Ligands
For this part of the experiment, the receptors and ligands were prepared into pdbqt format. To accomplish this part of the experiment the original mol2 files were used from the testset to convert these systems. The ligands will be assigned gasteiger charges and am1bcc charges will be assigned to the receptor, which produced the highest success rates in previous experiments and was performed in previous papers. Scripts were developed to process these systems from mol2 to pdbqt.
Command to convert these files
Step 1) Make sure you are in the correct directory
cd AutoDock4_Tutorial/
Step 2) Run the correct bash script to run these molecules
bash ./../run001.AutoDock4.system.prep.sh /gpfs/projects/rizzo/yuchzhou/RCR/DOCK_testset/clean.systems.all ../AutoDock4_Tutorial
This script will create a ligand and pdbqt receptor in each system directory
cd 121P/ ls
121P/121P.lig.am1bcc.pdbqt 121P/121P.rec.clean.pdbqt
Further Processing may be needed to prepare these systems, will explain later
This scripts used to accomplish this were prepare_ligand4.py and prepare_receptor4.py found in mgltools/1.5.6
IV.Preparing Grids
For this part of the experiment the grids will be generated for each ligand and receptor
Step 1) Enter the correct directory
cd AutoDock4_Tutorial
Step 2) Run the bash script that creates the grids, recommending submitting to the qsub
Important Note: This script uses the ligand location as the center of the grid position, since all ligands in these systems are already in the binding pocket
bash ./../run002.AutoDock4.grid.generation.sh /gpfs/projects/rizzo/yuchzhou/RCR/DOCK_testset/clean.systems.all ../AutoDock4_Tutorial > AutoDock4_grid_output
This will generate all of the grids by using the ligand and receptor previously generated, it's possible to edit the parameters in this script using the prepare_gpf4.py script by inputting new parameters such as the gridbox which is adjusted using the option npts='60,60,60' or the center of the box which uses the -y command to center the grid box around the ligand
Usage: prepare_gpf4.py -l pdbqt_file -r pdbqt_file
-l ligand_filename
-r receptor_filename
Optional parameters: [-i reference_gpf_filename] [-o output_gpf_filename] [-x flexres_filename] [-p parameter=newvalue. For example: -p ligand_types='HD,Br,A,C,OA' or p npts='60,60,66' or gridcenter='2.5,6.5,-7.5'] [-d directory of ligands to use to set types] [-y boolean to center grids on center of ligand] [-n boolean to NOT size_box_to_include_ligand] [-I increment npts in all 3 dimensions by this integer] [-v]
Following this cd into the 121P system directory
cd AutoDock4_Tutorial/121P/ ls
This will always generate the grids, .fld, .xyz, a variety of .map files will be generated for each chemical type present within the systems, and a log file of the results a .glg file
121P.autogrid.glg 121P.lig.am1bcc.pdbqt 121P.rec.clean.A.map 121P.rec.clean.e.map 121P.rec.clean.maps.fld 121P.rec.clean.N.map 121P.rec.clean.P.map 121P.rec.clean.C.map 121P.rec.clean.gpf 121P.rec.clean.maps.xyz 121P.rec.clean.OA.map 121P.rec.clean.d.map 121P.rec.clean.HD.map 121P.rec.clean.NA.map 121P.rec.clean.pdbqt
The commands used for this script was prepare_gpf4.py found in mgltools/1.5.6 and autogrid4 found in autodock/4.2.6
Trouble Shooting
Some of these systems may present issues such as zero charge atom types or non-integral charge systems(ex. is a ligand with a charge of 2.48) This should only occur with ligands because the receptors are maintaining their am1bcc charges.
Non-integral Charge Issue will look like this, and occur during the docking step
autodock4: *** Caution! Non-integral total charge (-2.498 e) on ligand may indicate a problem... ***
To trouble shoot this a script was developed to put all these problematic systems into a folder. These systems had then been prepared manually using Chimera to add gasteiger charges to all these systems.
This troubleshoot increases the success rate of the Pose Reproduction by 3%
Following all this the grids were regenerated for all these systems. Once these ligands, receptors, and grids have been generated once. You'll be able to reuse these systems and not need to repeat all the previous steps again.
The following is how to combat this issue
NEED TO DEVELOP SCRIPT TO PUT ALL THE NONINTEGRAL CHARGE AND ZERO CHARGED ATOMS INTO A FOLDER
Open up all the problematic systems in file
Open all the probematic systems folder
File->open->All_Ligands
Then add gasteiger charges to all the systems
Tools->Structure Editing->Add Charges
V.Docking Ligands
The following step will perform the actual AutoDock4 docking for this experiment. For this part of the experiment, it's possible to reuse the previously generated ligands, receptors, and grids to perform multiple docking experiments. This eliminates any variables that later bias in case systems were converted differently and to save time to prevent the user from rerunning all these steps again.
To conduct this experiment
cd AutoDock4_Tutorial
Following this run the script run003.AutoDock4.docking.sh Arguement 1 is the list of systems Arguement 2 is the directory were all the system directories are located Arguement 3 is the docking directory created for each docking experiment
bash ../run003.AutoDock4.docking.sh /gpfs/projects/rizzo/yuchzhou/RCR/DOCK_testset/clean.systems.all ../AutoDock4_Tutorial Tutorial_Docking
Once, this completed all the systems should look the same. Perform the ls command to see all files
ls
The following systems should show
121P.autogrid.glg 121P.lig.am1bcc.pdbqt 121P.rec.clean.A.map 121P.rec.clean.e.map 121P.rec.clean.maps.fld 121P.rec.clean.N.map 121P.rec.clean.P.map 121P.rec.clean.C.map 121P.rec.clean.gpf 121P.rec.clean.maps.xyz 121P.rec.clean.OA.map 121P.rec.clean.d.map 121P.rec.clean.HD.map 121P.rec.clean.NA.map 121P.rec.clean.pdbqt Tutorial_Docking/
Following this cd into the Tutorial_Docking/ and ls to view results
cd Tutorial_Docking/
ls
The following should be within the directory
121P.docking.dlg 121P.docking.dpf 121P.dock.parameter.dpf summary_of_results_1.0
