Dear Mark, Thanks for your quick answer.
Now, how to use gromacs 5.1.3 commands? The reason of my question: There is gromacs 4.5.4 (in /opt/bio directory) in my Rocks cluster system by default. I used source /usr/local/gromacs/bin/GMXRC, then pdb2gmx Unfortunately, pdb2gmx related to gromacs 4.5.4 is run. Please guide me to resolve this issue. Best, Atila -- Gromacs Users mailing list * Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/GMX-Users_List before posting! * Can't post? Read http://www.gromacs.org/Support/Mailing_Lists * For (un)subscribe requests visit https://maillist.sys.kth.se/mailman/listinfo/gromacs.org_gmx-users or send a mail to gmx-users-requ...@gromacs.org.