Virtual Screening
and
Hit Prioritization
Dr. Puneet Kacker
Amity University Uttar Pradesh
pkacker@amity.edu
Drug Discovery Process
http://www.lonza.com
What Medicinal Chemists Want?
Experiment Identification Binding
The Experimental Method
High-throughput screening (HTS)
Expensive Time Consuming Skill Intensive
Why Computational Methods?
Accuracy as good as experimental (not
always!)
Can provide insights at molecular level
Fast
Easy to access
Can easily be automated
Economical
Computational Limitations
It only can simulate real conditions if
programmed
Larger systems are less accurate then
smaller systems
Need to be experimentally tested for
accuracy.
Does not look at the whole picture
VLS: alternative of HTS
V
L
S
Millions of Compounds
Few Potential Binders
The Detailed VLS Process
Select a Target
Select a Compound Library
Prepare Target
Prepare Ligand set
Select a Docking Engine
Analyze the Results
Target Selection
Take one Disease
Search Therapeutic
Targets known for
that particular
disease
1 2
Selecting a Compound Library
Receptor Preparation
Add Hydrogen
Assign Charges
Assign Protonation
States
Complete Missing
Atoms
Ligand Preparation and VLS
Filters
Preparation
Assign charges
Generate possible Tautomers and
Stereoisomers (LigPrep)
Assign right protonation states
Filters
Physico-Chemical Filters (Lipinski Rule of
Five)
Similarity-based filters (take only diverse set
of compounds)
Docking Engines
Free 
Vina
DOCK
ArgusLab
Commercial
Cont…
Free
DOCK
AutoDock Vina
ArgusLab
VLS Hits Prioritization
Clustering Score based
Cont…
Interaction-based
Simple Docking Exercise
ArgusLab
The Target
ArgusLab Procedure
Defining a Binding Site
Defining a Ligand
Running Docking Simulation
Pose Energy
1
2
3
4
Challenges
Receptor Flexibility can
be tackled effectively by
exploiting Multiple diverse
Conformations of proteins
Multiple ways to
construct the ensemble:
Multiple crystal entries
Snapshots taken from MD
simulations
Figure: Hong and Tang, Biochemistry, Vol. 43, No. 16, 2004
Checking the Novelty
Scifinder
Writing Manuscript/Report
Stand on the shoulders of giants
Take suggestions and ideas from experts
(poster presentation)
Check Consistency
Select an appropriate journal
“Copyright” does not mean “right to copy”
(Check plagiarized material)
Reading Material
Journals Publishing Papers on
VLS
IF: 4.67IF: 1.79 IF:3.15 IF:5.25
Thanks!!
pkacker@amity.edu

Virtual Screening and Hit Prioritization