source leaprc.gaff loadamberprep pet.prepi loadamberprep hpt.prepi loadamberprep tpt.prepi mol = sequence {HPT PET PET PET PET PET PET PET PET PET PET PET PET PET PET PET PET PET PET TPT} savepdb mol pet20.pdb saveamberparm mol pet20.prmtop pet20.inpcrd quit