Hi everyone. I am trying to add three different types of solvent molecules in protein file by repeating following command three time. I am not sure how to center my protein via insert-molecules command but for now I am using trjconv command to center my protein after adding solvents (one by one) by this command. So, I have two questions here.

1). How to center protein by insert-molecules command?

2) is there a way to add more than one type of solvent molecules by running one time this command?

gmx_2018 insert-molecules -f prot.pdb -ci first-solvet.pdb -nmol 7396 -rot xyz -o prot-first--solvent.7396.pdb -box 16 16 16 -try 50

Kindly help me out. Thanks in advance.