1	6GO	6-O-methylguanine	1.000
2	SZL	6-methoxy-9h-purine	0.917
3	2BP	9h-purin-2-amine	0.833
4	6AP	9h-purine-2,6-diamine	0.769
5	6GU	6-chloroguanine	0.769
6	DX4	2-amino-1,9-dihydro-6h-purine-6-thione	0.769
7	GUN	Guanine	0.769
8	HH5	6-iodanyl-7~{H}-purin-2-amine	0.769
9	WUT	9~{H}-purine	0.750
10	8IG	8-iodo-guanine	0.714
11	9MG	9-methylguanine	0.714
12	A1IBK	2-azanyl-8-methyl-3,7-dihydropurine-6-thione	0.714
13	A1LXN	2-azanyl-8-methyl-1,9-dihydropurin-6-one	0.714
14	ANG	8-aminoguanine	0.714
15	B55	2-amino-8-sulfanyl-1,9-dihydro-6h-purin-6-one	0.714
16	BRG	8-bromoguanine	0.714
17	MY6	2-amino-7-methyl-1,7-dihydro-6h-purin-6-one	0.714
18	OXG	8-oxoguanine	0.714
19	W5M	9-methyl-9h-purine-2,6-diamine	0.714
20	MBP	1-[(2-amino-6,9-dihydro-1h-purin-6-yl)oxy]-3-methyl-2-butanol	0.706