1	BRG	8-bromoguanine	1.000
2	GUN	Guanine	0.917
3	8IG	8-iodo-guanine	0.846
4	9MG	9-methylguanine	0.846
5	A1LXN	2-azanyl-8-methyl-1,9-dihydropurin-6-one	0.846
6	ANG	8-aminoguanine	0.846
7	B55	2-amino-8-sulfanyl-1,9-dihydro-6h-purin-6-one	0.846
8	MY6	2-amino-7-methyl-1,7-dihydro-6h-purin-6-one	0.846
9	OXG	8-oxoguanine	0.846
10	2BP	9h-purin-2-amine	0.833
11	HPA	Hypoxanthine	0.833
12	NDM	7,9-dimethylguanine	0.786
13	2ON	2-sulfanyl-1,9-dihydro-6h-purin-6-one	0.769
14	6AP	9h-purine-2,6-diamine	0.769
15	6GU	6-chloroguanine	0.769
16	7DG	7-deazaguanine	0.769
17	9DG	9-deazaguanine	0.769
18	9QC	5-azanyl-3,6-dihydro-[1,2,3]triazolo[4,5-D]pyrimidin-7-one	0.769
19	AZG	5-amino-1h-[1,2,3]triazolo[4,5-D]pyrimidin-7-ol	0.769
20	BOA	2-bromo-6-hydroxy-purine	0.769
21	DX4	2-amino-1,9-dihydro-6h-purine-6-thione	0.769
22	HH5	6-iodanyl-7~{H}-purin-2-amine	0.769
23	QY8	2-amino-3h,4h,7h-pyrrolo[2,3-D]pyrimidin-4-one	0.769
24	XAN	Xanthine	0.769
25	WUT	9~{H}-purine	0.750
26	JU2	2-amino-6-bromo-4-oxo-4,7-dihydro-3h-pyrrolo[2,3-D]pyrimidine-5-carbonitrile	0.733
27	29H	2-aminopyrimido[4,5-D]pyrimidin-4(3h)-one	0.714
28	5JL	2,8-dithioxo-1,2,3,7,8,9-hexahydro-6h-purin-6-one	0.714
29	5JQ	2-thioxo-2,3,7,9-tetrahydro-1h-purine-6,8-dione	0.714
30	6GO	6-O-methylguanine	0.714
31	8HX	8-hydroxy-3,9-dihydro-1h-purine-2,6-dione	0.714
32	8TX	8-thioxo-3,7,8,9-tetrahydro-1h-purine-2,6-dione	0.714
33	A1IBK	2-azanyl-8-methyl-3,7-dihydropurine-6-thione	0.714
34	FDB	2-amino-5-methyl-3h-pyrrolo[2,3-D]pyrimidin-4(7h)-one	0.714
35	I7U	3-methyl-7~{H}-purine-2,6-dione	0.714
36	MOG	5-amino-2-methyl-6h-oxazolo[5,4-D]pyrimidin-7-one	0.714
37	PE0	Pterine	0.714
38	QBK	5-azanyl-[1,3]thiazolo[5,4-D]pyrimidine-2,7-dione	0.714
39	T0A	5-deazatetrahydropterin	0.714
40	URC	Uric acid	0.714
41	W5M	9-methyl-9h-purine-2,6-diamine	0.714