1 9DG 9-deazaguanine 1.000 2 9HX 9-deazahypoxanthine 0.909 3 GUN Guanine 0.833 4 8IG 8-iodo-guanine 0.769 5 9MG 9-methylguanine 0.769 6 A1LXN 2-azanyl-8-methyl-1,9-dihydropurin-6-one 0.769 7 ANG 8-aminoguanine 0.769 8 AQO 2-aminoquinazolin-4(3h)-one 0.769 9 B55 2-amino-8-sulfanyl-1,9-dihydro-6h-purin-6-one 0.769 10 BRG 8-bromoguanine 0.769 11 MOG 5-amino-2-methyl-6h-oxazolo[5,4-D]pyrimidin-7-one 0.769 12 MY6 2-amino-7-methyl-1,7-dihydro-6h-purin-6-one 0.769 13 OXG 8-oxoguanine 0.769 14 PE0 Pterine 0.769 15 QBK 5-azanyl-[1,3]thiazolo[5,4-D]pyrimidine-2,7-dione 0.769 16 2BP 9h-purin-2-amine 0.750 17 7HP 7-hydroxy-pyrazolo[4,3-D]pyrimidine 0.750 18 9DA 9-deazaadenine 0.750 19 A1H4L 1h-pyrrolo[3,2-B]pyridin-5-amine 0.750 20 HPA Hypoxanthine 0.750 21 PPO 3h-pyrazolo[4,3-D]pyrimidin-7-ol 0.750 22 44V (6s)-2-amino-6-methyl-5,6,7,8-tetrahydropteridin-4(3h)-one 0.714 23 44W 2-amino-6-methyl-7,8-dihydropteridin-4(3h)-one 0.714 24 7PD 2-aminopteridine-4,7(3h,8h)-dione 0.714 25 B60 2-amino-8-methyl-7,8-dihydropteridin-4(3h)-one 0.714 26 B62 (6r)-2-amino-6-methyl-5,6,7,8-tetrahydropteridin-4(3h)-one 0.714 27 DQU 2,6-diamino-3h-quinazolin-4-one 0.714 28 JSO 2-azanyl-6-methyl-3~{H}-pteridin-4-one 0.714 29 MAQ 2-amino-8-methylquinazolin-4(3h)-one 0.714 30 NDM 7,9-dimethylguanine 0.714 31 XHP 2-amino-6-methylidene-6,7-dihydropteridin-4(3h)-one 0.714 32 XTN 2-amino-1,5-dihydropteridine-4,6-dione 0.714