[gmx-users] T-coupling: System vs. Protein Sol?

[David Mathog]

There are various predefined groups which may be specified in the
tc-grps parameter file field.  The gmxdemo and speptide demos use
"Protein Sol" and the other demos use "System".

This is so not my field, but the members of the Protein and Sol
groups are in intimate contact with each other so in the real world
all of those elements would be in thermal equilibrium with each other.  

Why then use separate couplings to represent a protein system
in Gromacs?

Thanks,

David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech