{
  "modified_base" : {
    "name" : "Purine (a.k.a. nebularine or 9-beta-D-Ribofuranosyl)-9H-purine)",
    "sources" : [
      {
        "authors" : "Elizabeth A. Jolley and Brent M. Znosko",
        "title" : "The loss of a hydrogen bond: Thermodynamic contributions of a non-standard nucleotide",
        "journal" : "Nucleic Acids Research, Vol. 45, No. 3 1479-1487",
        "year" : 2017,
        "doi" : "10.1093/nar/gkw830"
      }
    ],
    "unmodified" : "A",
    "pairing_partners" : [
      "U"
    ],
    "one_letter_code" : "9",
    "fallback" : "A",
    "stacking_energies" : {
      "A9UU" :  0.43,
      "C9GU" :  -0.76,
      "G9CU" :  -1.1,
      "U9AU" :  0.33,
      "9AUU" :  -0.68,
      "9CUG" :  -1.98,
      "9GUC" :  -1.88,
      "9UUA" :  -0.32
    },
    "stacking_enthalpies" : {
      "A9UU" :  -14,
      "C9GU" :  -12.4,
      "G9CU" :  -14.2,
      "U9AU" :  -8.7,
      "9AUU" :  -10.4,
      "9CUG" :  -15.7,
      "9GUC" :  -14.5,
      "9UUA" :  -11.9
    },
    "terminal_energies" : {
      "9U" : 0.86,
      "U9" : 0.86
    },
    "terminal_enthalpies" : {
      "9U" : 2.3,
      "U9" : 2.3
    }
  }
}
