share/top/amber99sb.ff/rna.r2b

   1 ; rtp residue to rtp building block table
   2 ;GMX   Force-field
   3 A     RA        RA5     RA3     RAN
   4 U     RU        RU5     RU3     RUN
   5 C     RC        RC5     RC3     RCN
   6 G     RG        RG5     RG3     RGN