Dear Gromacs users, While I was using Gromos force field in simulating a protein in explicit solvent, I used the following parameters: rcoulomb = 1, rlist =1, rvdw = 1.4 Electrostatitcs : PME VDW : Twin range cutoff The above situation will not allow the calculation of any long-range electrostatics (LR-Coul) while calculating the energy of interaction among the specified energy groups of the the studied system. I am facing the question of to what extent that could affect the accuracy of the calculation of the energy of interaction among the specified energy groups of the the studied system. I argue that electrostatic interaction is mainly composed of H-bonds and salt-bridges, both with distance cutoffs of 0.35 nm and 0.4 nm respectively. So there should not be any need for calculating any electrostatic interaction beyond 1 nm (rcoulomb). On the other hand, I came across another argument that calculating the long range electrostatics is "complicated by the practical limitations of dividing lattice sum energies into energy groups". I could not find any explanation of this point in the Gromacs manual! But I assume this kind of argument could be valid if ignoring the long range electrostatics would drastically affect the accuracy of interaction energy calculations mentioned above. I would appreciate any feedback or comment concerning the above arguments. Thanks a lot Hassan
-- gmx-users mailing list [email protected] http://lists.gromacs.org/mailman/listinfo/gmx-users Please search the archive at http://www.gromacs.org/Support/Mailing_Lists/Search before posting! Please don't post (un)subscribe requests to the list. Use the www interface or send it to [email protected]. Can't post? Read http://www.gromacs.org/Support/Mailing_Lists

