GROMACS

make_ndx seems to be able to create groups greater than 30 characters, but can not later use them in new definitions. See the below output from version 4.6.5

Reading structure file
Going to read 1 old index file(s)

0 System              :  2105 atoms
  1 Protein             :  2105 atoms
  2 Protein-H           :  1018 atoms
  3 C-alpha             :   122 atoms
  4 Backbone            :   366 atoms
  5 MainChain           :   493 atoms
  6 MainChain+Cb        :   613 atoms
  7 MainChain+H         :   622 atoms
  8 SideChain           :  1483 atoms
  9 SideChain-H         :   525 atoms
 10 r_112_113_114_115_116_117_118_119_120_121_122_&_CA:    11 atoms

nr : group       !   'name' nr name   'splitch' nr    Enter: list groups
 'a': atom        &   'del' nr         'splitres' nr   'l': list residues
 't': atom type   |   'keep' nr        'splitat' nr    'h': help
 'r': residue         'res' nr         'chain' char
 "name": group        'case': case sensitive           'q': save and quit
 'ri': residue index

!r_112_113_114_115_116_117_118_119_120_121_122_&_CA

Name is too long, the maximum is 30 characters

Syntax error: "_112_113_114_115_116_117_118_119_120_121_122_&_CA"

!10

Copied index group 10 'r_112_113_114_115_116_117_118_119_120_121_122_&_CA'
Complemented group: 2094 atoms

11 !r_112_113_114_115_116_117_118_119_120_121_122_&_CA:  2094 atoms