The Nucleic Acid Modification Database

ID	Symbol	Common_Name	Chemical_Formula	Nucleoside_Mass	Description
14	1mG	1-methylguanine	C6H7N5O	165.16	Guanosine substituted with a methyl group at position N-1
15	2mG	2-methylguanine	C6H7N5O	165.16	A methylguanine in which the methyl group is located at the N2-position.
16	3mG	3-methylguanine	C6H7N5O	165.16	A methylguanine carrying the methyl substituent at position 3.
17	m6G	6-O-methylguanine	C6H7N5O	165.16	A methylguanine in which the methyl group is positioned on the oxygen at position 6.
18	7mG	7-methylguanine	C6H7N5O	165.16	A methylguanine that is guanine substituted by a methyl group at position 7.
19	8-oxo-G	8-oxoguanine	C5H3N5O2	165.11	An oxopurine that is guanine which is substituted by an oxo group at position 8.
20	ADG	7-amido-7-deazaguanosine	C12H15N5O6	325.28	A 7-deazaguanosine ribonucleoside that has 7-carbamoyl-7-deazaguanine as the nucleobase.
21	1,N(2)-ɛG	1,N2-ethenoguanine	C7H5N5O	175.15	A nucleobase analogue obtained by addition of an etheno group across positions 1 and N2 of guanine.
22	N(2),3-ɛG	N2,3-ethenoguanine	C7H5N5O	175.15	A nucleobase analogue obtained by addition of an etheno group across positions N2 and 3 of guanine.
23	m22G	N2,N2-dimethylguanosine	C12H17N5O5	311.3	A guanosine where the hydrogens of the amine group at C-2 are substituted by methyl groups.
24	CEG	N2-carboxyethylguanine	C8H9N5O3	223.19	An alanine derivative consisting of alanine having a 6-oxo-6,9-dihydro-1H-purin-2-yl group attached to the amino function.