I have a structure (.gro) file of a PolyEthylene Glycol (PEG) molecule as shown below. How do I get the corresponding structure file for PEG-20 i.e., a molecule with a degree of polymerization=20, containing only PEG molecules)
PEG 9 1PEG H 1 2.032 1.593 1.545 0.6568 2.5734 1.2192 1PEG C 2 1.929 1.614 1.508 0.1558 -0.2184 0.8547 1PEG H1 3 1.902 1.721 1.523 -3.6848 -0.3932 -3.0658 1PEG H2 4 1.921 1.588 1.400 -1.5891 1.4960 0.5057 1PEG O 5 1.831 1.544 1.576 0.0564 -0.5300 -0.6094 1PEG H3 6 1.676 1.665 1.494 -2.6585 -0.5997 0.3128 1PEG C1 7 1.699 1.559 1.519 0.6996 0.0066 0.2900 1PEG H4 8 1.699 1.500 1.425 4.2893 1.6837 -0.9462 1PEG H5 9 1.598 1.510 1.623 1.3303 1.7486 -1.1622 3.00000 3.00000 3.00000