thanks Egon W for giving answer,, @ Egon as you told me download 3d model and then convert into pdb files,,,it does work,,i got coordinates of my drug in openbabel software ,,, but i got stuck when these pdb files converting into pdb viewer.my question is how do we convert these pdb files coordinates into pdb viewer? i have discovery studio software for viewing pdb files.i am not able to convert these file coordinates into pdb form for further use.