1. LIGAND PREPARATION:

Ligand preparation further divided into different heading namely, ligand retrieval or collection, liand conversion and ligand analysis

a. Ligands Collection:
1. DRUGBANK :http://www.drugbank.ca/
first go to this link enter your protein or condition like any disease and disorder it will give you complete information about the drug which is designed for the particular purpose eg enter anxiety disorder in drugbank it will give you different ligands of that particular disorder and protein and also gives complete information about the target protein.
The DrugBank database is a unique bioinformatics and cheminformatics resource that combines detailed drug (i.e. chemical, pharmacological and pharmaceutical) data with comprehensive drug target (i.e. sequence, structure, and pathway) information. The database contains nearly 4800 drug entries including >1,480 FDA-approved small molecule drugs, 128 FDA-approved biotech (protein/peptide) drugs, 71 nutraceuticals and >3,200 experimental drugs. Additionally, more than 2,500 non-redundant protein (i.e. drug target) sequences are linked to these FDA approved drug entries. Each DrugCard entry contains more than 100 data fields with half of the information being devoted to drug/chemical data and the other half devoted to drug target or protein data.