Aminolink modification

The aminolink (or amino linker, amino-modifier, aminohexyl etc) modification allows amine-reactive (typically succinimidyl ester) dyes and other modfications to be added to oligonucleotides post-synthetically. The aminolink modification can be added at the 5′- or 3′- end of the oligo. Alkyl chains of different lengths can be used; the most common alkyl chain is the aminohexyl (C6) linker (Figure 1).

Structures of oligonucleotides containing 5'- and 3'- aminohexyl modifications. The aminohexyl moiety is coloured blue

Figure 1 | Structures of oligonucleotides containing 5′- and 3′- aminohexyl modifications. The aminohexyl moiety is coloured blue

Internal bases can also be modified with the aminohexyl group, allowing the attachment of amine-reactive dyes internally within the oligonucleotide. This requires the modified bases aminohexyl dA (amino-modifier C6 dA), aminohexyl dG (amino-modifier C6 dG), aminohexyl dC (amino-modifier C6 dC) and aminohexyl dT (amino-modifier C6 dT) (Figure 2).

Structures of aminohexyl-modified DNA bases

Figure 2 | Structures of aminohexyl-modified DNA bases

For further information about the reactivity of the aminohexyl modification see 5′-Aminohexyl oligonucleotides and post-synthetic labelling.